Summa Th. I EN Qu.12 a.7
Objection: 1. It seems that those who see the divine essence, comprehend God. For the Apostle says (Ph 3,12): "But I follow after, if I may by any means comprehend [Douay: 'apprehend']." But the Apostle did not follow in vain; for he said (1Co 9,26): "I . . . so run, not as at an uncertainty." Therefore he comprehended; and in the same way, others also, whom he invites to do the same, saying: "So run that you may comprehend."
2. Further, Augustine says (De Vid. Deum, Ep. cxlvii): "That is comprehended which is so seen as a whole, that nothing of it is hidden from the seer." But if God is seen in His essence, He is seen whole, and nothing of Him is hidden from the seer, since God is simple. Therefore whoever sees His essence, comprehends Him.
3. Further, if we say that He is seen as a "whole," but not "wholly," it may be contrarily urged that "wholly" refers either to the mode of the seer, or to the mode of the thing seen. But he who sees the essence of God, sees Him wholly, if the mode of the thing seen is considered; forasmuch as he sees Him as He is; also, likewise, he sees Him wholly if the mode of the seer is meant, forasmuch as the intellect will with its full power see the Divine essence. Therefore all who see the essence of God see Him wholly; therefore they comprehend Him.
On the contrary It is written: "O most mighty, great, and powerful, the Lord of hosts is Thy Name. Great in counsel, and incomprehensible in thought" (Jr 32,18-19). Therefore He cannot be comprehended.
I answer that It is impossible for any created intellect to comprehend God; yet "for the mind to attain to God in some degree is great beatitude," as Augustine says (De Verb. Dim., Serm. xxxvii).
In proof of this we must consider that what is comprehended is perfectly known; and that is perfectly known which is known so far as it can be known. Thus, if anything which is capable of scientific demonstration is held only by an opinion resting on a probably proof, it is not comprehended; as, for instance, if anyone knows by scientific demonstration that a triangle has three angles equal to two right angles, he comprehends that truth; whereas if anyone accepts it as a probable opinion because wise men or most men teach it, he cannot be said to comprehend the thing itself, because he does not attain to that perfect mode of knowledge of which it is intrinsically capable. But no created intellect can attain to that perfect mode of the knowledge of the Divine intellect whereof it is intrinsically capable. Which thus appears---Everything is knowable according to its actuality. But God, whose being is infinite, as was shown above (Question [7]) is infinitely knowable. Now no created intellect can know God infinitely. For the created intellect knows the Divine essence more or less perfectly in proportion as it receives a greater or lesser light of glory. Since therefore the created light of glory received into any created intellect cannot be infinite, it is clearly impossible for any created intellect to know God in an infinite degree. Hence it is impossible that it should comprehend God.
Reply to Objection: 1. "Comprehension" is twofold: in one sense it is taken strictly and properly, according as something is included in the one comprehending; and thus in no way is God comprehended either by intellect, or in any other way; forasmuch as He is infinite and cannot be included in any finite being; so that no finite being can contain Him infinitely, in the degree of His own infinity. In this sense we now take comprehension. But in another sense "comprehension" is taken more largely as opposed to "non-attainment"; for he who attains to anyone is said to comprehend him when he attains to him. And in this sense God is comprehended by the blessed, according to the words, "I held him, and I will not let him go" (Ct 3,4); in this sense also are to be understood the words quoted from the Apostle concerning comprehension. And in this way "comprehension" is one of the three prerogatives of the soul, responding to hope, as vision responds to faith, and fruition responds to charity. For even among ourselves not everything seen is held or possessed, forasmuch as things either appear sometimes afar off, or they are not in our power of attainment. Neither, again, do we always enjoy what we possess; either because we find no pleasure in them, or because such things are not the ultimate end of our desire, so as to satisfy and quell it. But the blessed possess these three things in God; because they see Him, and in seeing Him, possess Him as present, having the power to see Him always; and possessing Him, they enjoy Him as the ultimate fulfilment of desire.
2. God is called incomprehensible not because anything of Him is not seen; but because He is not seen as perfectly as He is capable of being seen; thus when any demonstrable proposition is known by probable reason only, it does not follow that any part of it is unknown, either the subject, or the predicate, or the composition; but that it is not as perfectly known as it is capable of being known. Hence Augustine, in his definition of comprehension, says the whole is comprehended when it is seen in such a way that nothing of it is hidden from the seer, or when its boundaries can be completely viewed or traced; for the boundaries of a thing are said to be completely surveyed when the end of the knowledge of it is attained.
3. The word "wholly" denotes a mode of the object; not that the whole object does not come under knowledge, but that the mode of the object is not the mode of the one who knows. Therefore he who sees God's essence, sees in Him that He exists infinitely, and is infinitely knowable; nevertheless, this infinite mode does not extend to enable the knower to know infinitely; thus, for instance, a person can have a probable opinion that a proposition is demonstrable, although he himself does not know it as demonstrated.
Objection: 1. It seems that those who see the essence of God see all things in God. For Gregory says (Dialog. iv): "What do they not see, who see Him Who sees all things?" But God sees all things. Therefore those who see God see all things.
2. Further, whoever sees a mirror, sees what is reflected in the mirror. But all actual or possible things shine forth in God as in a mirror; for He knows all things in Himself. Therefore whoever sees God, sees all actual things in Him, and also all possible things.
3. Further, whoever understands the greater, can understand the least, as is said in De Anima iii. But all that God does, or can do, are less than His essence. Therefore whoever understands God, can understand all that God does, or can do.
4. Further, the rational creature naturally desires to know all things. Therefore if in seeing God it does not know all things, its natural desire will not rest satisfied; thus, in seeing God it will not be fully happy; which is incongruous. Therefore he who sees God knows all things.
On the contrary The angels see the essence of God; and yet do not know all things. For as Dionysius says (Coel. Hier. vii), "the inferior angels are cleansed from ignorance by the superior angels." Also they are ignorant of future contingent things, and of secret thoughts; for this knowledge belongs to God alone. Therefore whosoever sees the essence of God, does not know all things.
I answer that The created intellect, in seeing the divine essence, does not see in it all that God does or can do. For it is manifest that things are seen in God as they are in Him. But all other things are in God as effects are in the power of their cause. Therefore all things are seen in God as an effect is seen in its cause. Now it is clear that the more perfectly a cause is seen, the more of its effects can be seen in it. For whoever has a lofty understanding, as soon as one demonstrative principle is put before him can gather the knowledge of many conclusions; but this is beyond one of a weaker intellect, for he needs things to be explained to him separately. And so an intellect can know all the effects of a cause and the reasons for those effects in the cause itself, if it comprehends the cause wholly. Now no created intellect can comprehend God wholly, as shown above (Article [7]). Therefore no created intellect in seeing God can know all that God does or can do, for this would be to comprehend His power; but of what God does or can do any intellect can know the more, the more perfectly it sees God.
Reply to Objection: 1. Gregory speaks as regards the object being sufficient, namely, God, who in Himself sufficiently contains and shows forth all things; but it does not follow that whoever sees God knows all things, for he does not perfectly comprehend Him.
2. It is not necessary that whoever sees a mirror should see all that is in the mirror, unless his glance comprehends the mirror itself.
3. Although it is more to see God than to see all things else, still it is a greater thing to see Him so that all things are known in Him, than to see Him in such a way that not all things, but the fewer or the more, are known in Him. For it has been shown in this article that the more things are known in God according as He is seen more or less perfectly.
4. The natural desire of the rational creature is to know everything that belongs to the perfection of the intellect, namely, the species and the genera of things and their types, and these everyone who sees the Divine essence will see in God. But to know other singulars, their thoughts and their deeds does not belong to the perfection of the created intellect nor does its natural desire go out to these things; neither, again, does it desire to know things that exist not as yet, but which God can call into being. Yet if God alone were seen, Who is the fount and principle of all being and of all truth, He would so fill the natural desire of knowledge that nothing else would be desired, and the seer would be completely beatified. Hence Augustine says (Confess. v): "Unhappy the man who knoweth all these" (i.e. all creatures) "and knoweth not Thee! but happy whoso knoweth Thee although he know not these. And whoso knoweth both Thee and them is not the happier for them, but for Thee alone."
Objection: 1. It seems that what is seen in God by those who see the Divine essence, is seen by means of some similitude. For every kind of knowledge comes about by the knower being assimilated to the object known. For thus the intellect in act becomes the actual intelligible, and the sense in act becomes the actual sensible, inasmuch as it is informed by a similitude of the object, as the eye by the similitude of color. Therefore if the intellect of one who sees the Divine essence understands any creatures in God, it must be informed by their similitudes.
2. Further, what we have seen, we keep in memory. But Paul, seeing the essence of God whilst in ecstasy, when he had ceased to see the Divine essence, as Augustine says (Gn ad lit. ii, 28,34), remembered many of the things he had seen in the rapture; hence he said: "I have heard secret words which it is not granted to man to utter" (2Co 12,4). Therefore it must be said that certain similitudes of what he remembered, remained in his mind; and in the same way, when he actually saw the essence of God, he had certain similitudes or ideas of what he actually saw in it.
On the contrary A mirror and what is in it are seen by means of one likeness. But all things are seen in God as in an intelligible mirror. Therefore if God Himself is not seen by any similitude but by His own essence, neither are the things seen in Him seen by any similitudes or ideas.
I answer that Those who see the divine essence see what they see in God not by any likeness, but by the divine essence itself united to their intellect. For each thing is known in so far as its likeness is in the one who knows. Now this takes place in two ways. For as things which are like one and the same thing are like to each other, the cognitive faculty can be assimilated to any knowable object in two ways. In one way it is assimilated by the object itself, when it is directly informed by a similitude, and then the object is known in itself. In another way when informed by a similitude which resembles the object; and in this way, the knowledge is not of the thing in itself, but of the thing in its likeness. For the knowledge of a man in himself differs from the knowledge of him in his image. Hence to know things thus by their likeness in the one who knows, is to know them in themselves or in their own nature; whereas to know them by their similitudes pre-existing in God, is to see them in God. Now there is a difference between these two kinds of knowledge. Hence, according to the knowledge whereby things are known by those who see the essence of God, they are seen in God Himself not by any other similitudes but by the Divine essence alone present to the intellect; by which also God Himself is seen.
Reply to Objection: 1. The created intellect of one who sees God is assimilated to what is seen in God, inasmuch as it is united to the Divine essence, in which the similitudes of all things pre-exist.
2. Some of the cognitive faculties form other images from those first conceived; thus the imagination from the preconceived images of a mountain and of gold can form the likeness of a golden mountain; and the intellect, from the preconceived ideas of genus and difference, forms the idea of species; in like manner from the similitude of an image we can form in our minds the similitude of the original of the image. Thus Paul, or any other person who sees God, by the very vision of the divine essence, can form in himself the similitudes of what is seen in the divine essence, which remained in Paul even when he had ceased to see the essence of God. Still this kind of vision whereby things are seen by this likeness thus conceived, is not the same as that whereby things are seen in God.
Objection: 1. It seems that those who see the essence of God do not see all they see in Him at one and the same time. For according to the Philosopher (Topic. ii): "It may happen that many things are known, but only one is understood." But what is seen in God, is understood; for God is seen by the intellect. Therefore those who see God do not see all in Him at the same time.
2. Further, Augustine says (Gn ad lit. viii, 22,23), "God moves the spiritual creature according to time"---i.e. by intelligence and affection. But the spiritual creature is the angel who sees God. Therefore those who see God understand and are affected successively; for time means succession.
On the contrary Augustine says (De Trin. xvi): "Our thoughts will not be unstable, going to and fro from one thing to another; but we shall see all we know at one glance."
I answer that What is seen in the Word is seen not successively, but at the same time. In proof whereof, we ourselves cannot know many things all at once, forasmuch as understand many things by means of many ideas. But our intellect cannot be actually informed by many diverse ideas at the same time, so as to understand by them; as one body cannot bear different shapes simultaneously. Hence, when many things can be understood by one idea, they are understood at the same time; as the parts of a whole are understood successively, and not all at the same time, if each one is understood by its own idea; whereas if all are understood under the one idea of the whole, they are understood simultaneously. Now it was shown above that things seen in God, are not seen singly by their own similitude; but all are seen by the one essence of God. Hence they are seen simultaneously, and not successively.
Reply to Objection: 1. We understand one thing only when we understand by one idea; but many things understood by one idea are understood simultaneously, as in the idea of a man we understand "animal" and "rational"; and in the idea of a house we understand the wall and the roof.
2.: As regards their natural knowledge, whereby they know things by diverse ideas given them, the angels do not know all things simultaneously, and thus they are moved in the act of understanding according to time; but as regards what they see in God, they see all at the same time.
Objection: 1. It seems that one can in this life see the Divine essence. For Jacob said: "I have seen God face to face" (Gn 32,30). But to see Him face to face is to see His essence, as appears from the words: "We see now in a glass and in a dark manner, but then face to face" (1Co 13,12).
2. Further, the Lord said to Moses: "I speak to him mouth to mouth, and plainly, and not by riddles and figures doth he see the Lord" (Nb 12,8); but this is to see God in His essence. Therefore it is possible to see the essence of God in this life.
3. Further, that wherein we know all other things, and whereby we judge of other things, is known in itself to us. But even now we know all things in God; for Augustine says (Confess. viii): "If we both see that what you say is true, and we both see that what I say is true; where, I ask, do we see this? neither I in thee, nor thou in me; but both of us in the very incommutable truth itself above our minds." He also says (De Vera Relig. xxx) that, "We judge of all things according to the divine truth"; and (De Trin. xii) that, "it is the duty of reason to judge of these corporeal things according to the incorporeal and eternal ideas; which unless they were above the mind could not be incommutable." Therefore even in this life we see God Himself.
4. Further, according to Augustine (Gn ad lit. xii, 24, 25), those things that are in the soul by their essence are seen by intellectual vision. But intellectual vision is of intelligible things, not by similitudes, but by their very essences, as he also says (Gn ad lit. xiii, 24,25). Therefore since God is in our soul by His essence, it follows that He is seen by us in His essence.
On the contrary It is written, "Man shall not see Me, and live" (Ex 32,20), and a gloss upon this says, "In this mortal life God can be seen by certain images, but not by the likeness itself of His own nature."
I answer that God cannot be seen in His essence by a mere human being, except he be separated from this mortal life. The reason is because, as was said above (Article [4]), the mode of knowledge follows the mode of the nature of the knower. But our soul, as long as we live in this life, has its being in corporeal matter; hence naturally it knows only what has a form in matter, or what can be known by such a form. Now it is evident that the Divine essence cannot be known through the nature of material things. For it was shown above (Articles [2],9) that the knowledge of God by means of any created similitude is not the vision of His essence. Hence it is impossible for the soul of man in this life to see the essence of God. This can be seen in the fact that the more our soul is abstracted from corporeal things, the more it is capable of receiving abstract intelligible things. Hence in dreams and alienations of the bodily senses divine revelations and foresight of future events are perceived the more clearly. It is not possible, therefore, that the soul in this mortal life should be raised up to the supreme of intelligible objects, i.e. to the divine essence.
Reply to Objection: 1. According to Dionysius (Coel. Hier. iv) a man is said in the Scriptures to see God in the sense that certain figures are formed in the senses or imagination, according to some similitude representing in part the divinity. So when Jacob says, "I have seen God face to face," this does not mean the Divine essence, but some figure representing God. And this is to be referred to some high mode of prophecy, so that God seems to speak, though in an imaginary vision; as will later be explained (II-II 174,0) in treating of the degrees of prophecy. We may also say that Jacob spoke thus to designate some exalted intellectual contemplation, above the ordinary state.
2. As God works miracles in corporeal things, so also He does supernatural wonders above the common order, raising the minds of some living in the flesh beyond the use of sense, even up to the vision of His own essence; as Augustine says (Gn ad lit. xii, 26,27,28) of Moses, the teacher of the Jews; and of Paul, the teacher of the Gentiles. This will be treated more fully in the question of rapture (II-II 175,0).
3. All things are said to be seen in God and all things are judged in Him, because by the participation of His light, we know and judge all things; for the light of natural reason itself is a participation of the divine light; as likewise we are said to see and judge of sensible things in the sun, i.e., by the sun's light. Hence Augustine says (Soliloq. i, 8), "The lessons of instruction can only be seen as it were by their own sun," namely God. As therefore in order to see a sensible object, it is not necessary to see the substance of the sun, so in like manner to see any intelligible object, it is not necessary to see the essence of God.
4. Intellectual vision is of the things which are in the soul by their essence, as intelligible things are in the intellect. And thus God is in the souls of the blessed; not thus is He in our soul, but by presence, essence and power.
Objection: 1. It seems that by natural reason we cannot know God in this life. For Boethius says (De Consol. v) that "reason does not grasp simple form." But God is a supremely simple form, as was shown above (Question [3], Article [7]). Therefore natural reason cannot attain to know Him.
2. Further, the soul understands nothing by natural reason without the use of the imagination. But we cannot have an imagination of God, Who is incorporeal. Therefore we cannot know God by natural knowledge.
3. Further, the knowledge of natural reason belongs to both good and evil, inasmuch as they have a common nature. But the knowledge of God belongs only to the good; for Augustine says (De Trin. i): "The weak eye of the human mind is not fixed on that excellent light unless purified by the justice of faith." Therefore God cannot be known by natural reason.
On the contrary It is written (Rm 1,19), "That which is known of God," namely, what can be known of God by natural reason, "is manifest in them."
I answer that Our natural knowledge begins from sense. Hence our natural knowledge can go as far as it can be led by sensible things. But our mind cannot be led by sense so far as to see the essence of God; because the sensible effects of God do not equal the power of God as their cause. Hence from the knowledge of sensible things the whole power of God cannot be known; nor therefore can His essence be seen. But because they are His effects and depend on their cause, we can be led from them so far as to know of God "whether He exists," and to know of Him what must necessarily belong to Him, as the first cause of all things, exceeding all things caused by Him.
Hence we know that His relationship with creatures so far as to be the cause of them all; also that creatures differ from Him, inasmuch as He is not in any way part of what is caused by Him; and that creatures are not removed from Him by reason of any defect on His part, but because He superexceeds them all.
Reply to Objection: 1. Reason cannot reach up to simple form, so as to know "what it is"; but it can know "whether it is."
2. God is known by natural knowledge through the images of His effects.
3. As the knowledge of God's essence is by grace, it belongs only to the good; but the knowledge of Him by natural reason can belong to both good and bad; and hence Augustine says (Retract. i), retracting what he had said before: "I do not approve what I said in prayer, 'God who willest that only the pure should know truth.' For it can be answered that many who are not pure can know many truths," i.e. by natural reason.
Objection: 1. It seems that by grace a higher knowledge of God is not obtained than by natural reason. For Dionysius says (De Mystica Theol. i) that whoever is the more united to God in this life, is united to Him as to one entirely unknown. He says the same of Moses, who nevertheless obtained a certain excellence by the knowledge conferred by grace. But to be united to God while ignoring of Him "what He is," comes about also by natural reason. Therefore God is not more known to us by grace than by natural reason.
2. Further, we can acquire the knowledge of divine things by natural reason only through the imagination; and the same applies to the knowledge given by grace. For Dionysius says (Coel. Hier. i) that "it is impossible for the divine ray to shine upon us except as screened round about by the many colored sacred veils." Therefore we cannot know God more fully by grace than by natural reason.
3. Further, our intellect adheres to God by grace of faith. But faith does not seem to be knowledge; for Gregory says (Hom. xxvi in ) that "things not seen are the objects of faith, and not of knowledge." Therefore there is not given to us a more excellent knowledge of God by grace.
On the contrary The Apostle says that "God hath revealed to us His spirit," what "none of the princes of this world knew" (1Co 2,10), namely, the philosophers, as the gloss expounds.
I answer that We have a more perfect knowledge of God by grace than by natural reason. Which is proved thus. The knowledge which we have by natural reason contains two things: images derived from the sensible objects; and the natural intelligible light, enabling us to abstract from them intelligible conceptions.
Now in both of these, human knowledge is assisted by the revelation of grace. For the intellect's natural light is strengthened by the infusion of gratuitous light; and sometimes also the images in the human imagination are divinely formed, so as to express divine things better than those do which we receive from sensible objects, as appears in prophetic visions; while sometimes sensible things, or even voices, are divinely formed to express some divine meaning; as in the Baptism, the Holy Ghost was seen in the shape of a dove, and the voice of the Father was heard, "This is My beloved Son" (Mt 3,17).
Reply to Objection: 1. Although by the revelation of grace in this life we cannot know of God "what He is," and thus are united to Him as to one unknown; still we know Him more fully according as many and more excellent of His effects are demonstrated to us, and according as we attribute to Him some things known by divine revelation, to which natural reason cannot reach, as, for instance, that God is Three and One.
2. From the images either received from sense in the natural order, or divinely formed in the imagination, we have so much the more excellent intellectual knowledge, the stronger the intelligible light is in man; and thus through the revelation given by the images a fuller knowledge is received by the infusion of the divine light.
3. Faith is a kind of knowledge, inasmuch as the intellect is determined by faith to some knowable object. But this determination to one object does not proceed from the vision of the believer, but from the vision of Him who is believed. Thus as far as faith falls short of vision, it falls short of the knowledge which belongs to science, for science determines the intellect to one object by the vision and understanding of first principles.
After the consideration of those things which belong to the divine knowledge, we now proceed to the consideration of the divine names. For everything is named by us according to our knowledge of it.
Under this head, there are twelve points for inquiry:
(1) Whether God can be named by us?
(2) Whether any names applied to God are predicated of Him substantially?
(3) Whether any names applied to God are said of Him literally, or are all to be taken metaphorically?
(4) Whether any names applied to God are synonymous?
(5) Whether some names are applied to God and to creatures univocally or equivocally?
(6) Whether, supposing they are applied analogically, they are applied first to God or to creatures?
(7) Whether any names are applicable to God from time?
(8) Whether this name "God" is a name of nature, or of the operation?
(9) Whether this name "God" is a communicable name?
(10) Whether it is taken univocally or equivocally as signifying God, by nature, by participation, and by opinion?
(11) Whether this name, "Who is," is the supremely appropriate name of God?
(12) Whether affirmative propositions can be formed about God?
Objection: 1. It seems that no name can be given to God. For Dionysius says (Div. Nom. i) that, "Of Him there is neither name, nor can one be found of Him;" and it is written: "What is His name, and what is the name of His Son, if thou knowest?" (Pr 30,4).
2. Further, every name is either abstract or concrete. But concrete names do not belong to God, since He is simple, nor do abstract names belong to Him, forasmuch as they do not signify any perfect subsisting thing. Therefore no name can be said of God.
3. Further, nouns are taken to signify substance with quality; verbs and participles signify substance with time; pronouns the same with demonstration or relation. But none of these can be applied to God, for He has no quality, nor accident, nor time; moreover, He cannot be felt, so as to be pointed out; nor can He be described by relation, inasmuch as relations serve to recall a thing mentioned before by nouns, participles, or demonstrative pronouns. Therefore God cannot in any way be named by us.
On the contrary It is written (Ex 15,3): "The Lord is a man of war, Almighty is His name."
I answer that Since according to the Philosopher (Peri Herm. i), words are signs of ideas, and ideas the similitude of things, it is evident that words relate to the meaning of things signified through the medium of the intellectual conception. It follows therefore that we can give a name to anything in as far as we can understand it. Now it was shown above (Question [12], Articles [11],12) that in this life we cannot see the essence of God; but we know God from creatures as their principle, and also by way of excellence and remotion. In this way therefore He can be named by us from creatures, yet not so that the name which signifies Him expresses the divine essence in itself. Thus the name "man" expresses the essence of man in himself, since it signifies the definition of man by manifesting his essence; for the idea expressed by the name is the definition.
Reply to Objection: 1. The reason why God has no name, or is said to be above being named, is because His essence is above all that we understand about God, and signify in word.
2. Because we know and name God from creatures, the names we attribute to God signify what belongs to material creatures, of which the knowledge is natural to us. And because in creatures of this kind what is perfect and subsistent is compound; whereas their form is not a complete subsisting thing, but rather is that whereby a thing is; hence it follows that all names used by us to signify a complete subsisting thing must have a concrete meaning as applicable to compound things; whereas names given to signify simple forms, signify a thing not as subsisting, but as that whereby a thing is; as, for instance, whiteness signifies that whereby a thing is white. And as God is simple, and subsisting, we attribute to Him abstract names to signify His simplicity, and concrete names to signify His substance and perfection, although both these kinds of names fail to express His mode of being, forasmuch as our intellect does not know Him in this life as He is.
3. To signify substance with quality is to signify the "suppositum" with a nature or determined form in which it subsists. Hence, as some things are said of God in a concrete sense, to signify His subsistence and perfection, so likewise nouns are applied to God signifying substance with quality. Further, verbs and participles which signify time, are applied to Him because His eternity includes all time. For as we can apprehend and signify simple subsistences only by way of compound things, so we can understand and express simple eternity only by way of temporal things, because our intellect has a natural affinity to compound and temporal things. But demonstrative pronouns are applied to God as describing what is understood, not what is sensed. For we can only describe Him as far as we understand Him. Thus, according as nouns, participles and demonstrative pronouns are applicable to God, so far can He be signified by relative pronouns.
Summa Th. I EN Qu.12 a.7