Since it has now been proved from divine Scripture that there are true joys in the kingdom of God, we shall now set forth what these joys are. First we must briefly explain the joys of the understanding, of the will, and of the memory, which belong to the spirit; then the joys of each of the senses, which belong to the body. Nor do we intend in this place to assert that the understanding, the memory, and the senses of the body are the proper seat of joy; for we are not unaware that joy, like desire, properly belongs to the will in the higher part of the soul. But we speak as men commonly speak, who do not hesitate to say that the eye is delighted by the beauty of color and the ear by the sweetness of sound. By the joy of the mind, then, or of the memory, or of the external senses, we mean the delight which a man perceives from the things he understands, or of which he has remembrance, or which he draws in through the outward senses.
The first joy of the blessed, then, will be to see God with the eyes of the mind, face to face, as St. Paul says in the First Epistle to the Corinthians (1 Cor. 13:12), and to see Him as He is, as St. John says in his First Epistle (1 John 3:2). How great this joy will be, we may conjecture from the fact that the prophet Isaiah (Isa. 64:4) and the Apostle Paul testify that it surpasses all the joys which no man has seen, or heard, or desired, or conceived: "Eye has not seen, nor ear heard, nor has it entered into the heart of man, what things God has prepared for those who love Him" (1 Cor. 2:9). For Scripture here speaks of the principal and essential beatitude, which consists in the very vision of God, according to the word of the Lord: "Blessed are the clean of heart, for they shall see God" (Matt. 5:8); and "This is eternal life, that they may know You, the only true God, and Jesus Christ, whom You have sent" (John 17:3). And indeed that seems a great amplification — that no one has seen, or heard, or desired, or conceived such a good as will be perceived in the vision of God; yet it is not an amplification but the simple truth. For the eyes, the ears, and the hearts of men are wont to perceive only bounded, measured, and finite joys; but the vision of God is a vision of inaccessible light and of a good utterly infinite, which contains in itself every good — according to the word of the Lord to Moses, "I will show you all good" (Exod. 33:19), when he had first asked, "Show me Your face." But to demonstrate this same point by reason, it should be known from St. Thomas (I-II, q. 32, art. 2) that the delight which is perceived from knowledge requires three things: a power that understands or senses, an object suited to that power, and the union of the object with the power; and the more apt the power is for knowing, the nobler the object, and the more intimate the union, the greater the delight that is perceived. Now, that the understanding or mind is purer, loftier, nobler, and, so to speak, more lively, and therefore far more apt for knowing than the external sense, cannot be called into doubt. And that God is the highest and noblest object, not only above all the objects of the senses, but even above absolutely all objects of the mind — being infinite good, and every good, or rather goodness itself — no one can doubt. Moreover, that the union of the understanding with God through open vision is a most intimate union — so that the essence of God penetrates the whole mind of man, and the mind itself is wholly plunged into God Himself and transformed, as into a great sea — is equally certain and beyond doubt. Who, then, can grasp or even surmise how great that joy is? What a kiss of the supreme Good! What an embrace of the Bridegroom of infinite beauty! Certainly, in the union of a beautiful color with the sense of sight, of the sweetest sound with the sense of hearing, and of the other sensible things with their own senses, we experience great pleasure — and often so great that some men nearly lose their minds on account of it; and yet the sentient powers are material and common to us with the beasts, the objects also are corporeal things which harm as often as they delight, and finally the union is superficial and external, and in most of the senses it is not the object itself that is united with the power, but its image. Add that the spiritual union — the union of God with the understanding through vision — is firmer, more lasting, and whole all at once; for bodily delights perceived by the senses, since they bring change, cannot be enduring, nor are they whole at once, but are instilled as it were drop by drop. Wherefore, beyond all doubt, the delight of the mind is greater than that of the senses.
Gather yourself therefore, O man, and weigh in a just balance the pleasure that the world offers you with that which God promises, since He promises the vision of Himself to those who love Him, and choose what you will. For surely, if you love pleasure — which you cannot deny that you love — you will choose the greatest rather than the least, and that which will last forever rather than that which is but for a moment. Nor is the vision of God alone promised to the blessed in heaven, but also the vision of all things that God has made. Here indeed on earth we discern through the sense of sight the sun, and the moon, and the stars, and lands and seas, and rivers, and animals, and trees, and metals; but our mind discerns nothing at all — that is, it knows no created substance perfectly, not its essential differences, not its properties, not its powers — and a man does not even see his own soul, but, in the manner of the blind, by groping at effects and running to and fro through reasoning, acquires some knowledge. How great a joy, then, will it be, when our intellect, with unveiled face, shall plainly see the natures of all things — their differences, their properties, their powers? And with how great an exultation will it be amazed, when it shall see the innumerable army of the Angels, no one of whom shares a species with another, and shall distinctly behold the differences of all and of each? Ah, what a theater that will be, how desirable, how lovely — when it will be granted to behold the blessed, who have lived from the beginning of the world to the end, gathered together with all the Angels, and the merits, palms, and crowns of each one! Nor shall we look without joy and pleasure upon the crimes and the torments of the damned, in which the holiness of the pious and the justice of God will wondrously shine forth: for then the just shall wash their hands in the blood of sinners (Ps. 57:11), as the Prophet foretold so long beforehand. For what is it to wash one's hands in the blood of sinners, if not that the works of the just shine out more brightly by comparison with the works of wicked men? Surely the virginity of some will shine the more when it is compared with the adulteries of others of like condition; and likewise the fastings and almsdeeds of some, when they are compared with the revelry, and drunkenness, and cruelty of others of like condition — namely, when there will be those who say: "That man was young and handsome, and yet he kept virginity or chastity all his life; but this man was also young and handsome, and, not content with his wife, often defiled himself with adulteries and sacrileges; and that man was rich and noble, and he fasted, and prayed frequently, and gave many alms; this man was equally rich and noble, but, given over to revelry and drunkenness, he so consumed everything on his pleasures that he never gave anything to the poor." And hence it will come to pass that the joy of the just will grow from the knowledge of the crimes of the wicked; and at the same time their joy will grow from the contemplation of the justice that will wondrously shine in the rewards of the blessed and in the punishments of the wretched. For now in human affairs a great deformity is seen in this, that often guilt is joined with reward, and virtue with punishment — whence the justice of God seems to be obscured not a little among men: but then every punishment will be joined with guilt, and every reward with virtue; and so the beauty of justice will stir up incredible joy in the minds of the blessed.