2 But as we have already, in a way proportionate to the brevity of our discourse, spoken of the objects of the promise, and of its own stability; let us now look at this one point, as far as we are able, what it is that He was pleased to promise when He said, “I will that they also whom You have given me be with me where I am.” As far as pertains to the creaturehood wherein He was made of the seed of David according to the flesh, not even He Himself was yet where He would afterwards be: but He could say in this way, “where I am,” to let us understand that He was soon to ascend into heaven, so that He spoke of Himself as being already there, where He was presently to be.
He could do so also in the same way as He had said on a former occasion, when speaking to Nicodemus, “No man ascends into heaven, save He that came down from heaven, even the Son of man who is in heaven.” For there also He did not say, Will be, but “is,” because of the oneness of person, wherein God is at once man, and man God. He promised, therefore, that we should be in heaven; for there the servant-form, which He received of the Virgin, has been elevated, and set at the right hand of the Father.
Because of the same blessed hope the apostle also says: “But God, who is rich in mercy, for His great love wherewith He loved us, even when we were dead in sins, has quickened us together with Christ; by whose grace we are saved; and has raised us up together, and made us sit together in heavenly places in Christ Jesus.” And so accordingly we may understand the Lord to have said, “That where I am, there they may be also.” He, indeed, said of Himself that He was there already; but of us He merely declared that He wished us to be there with Him, without any indication that we were there already.
But what the Lord said that He wished to be done, the apostle spoke of as already accomplished. For he said not, He will yet raise us up, and make us sit in heavenly places; but, “has raised us up, and made us sit in heavenly places:” for it is not without good grounds, but in believing assurance, that he reckons as already done what he is certain will yet be done. But if it is in respect of the form of God, wherein He is equal to the Father, that we would be inclined to understand His words, “I will that they also be with me, where I am,” let our mind get quit of every thought of material images: whatever the soul has had presented to it, that is endowed with length, or breadth, or thickness, tinted by the light with any sort of bodily hue, or diffused through local space of any kind, whether finite or infinite, let it, as far as possible, turn away from all such notions the glance of its contemplation on the inward bent of its thoughts.
And let us not be making inquiries as to where the Son, the Father's co-equal, is, since no one has yet found out where He is not. But if any one would inquire, let him inquire rather how he may be with Him; not everywhere as He is, but wherever He may be. For when He said to the man that was expiating his crimes on the tree, and making confession unto salvation, “Today shall you be with me in paradise,” in respect to His human nature His own soul was on that very day to be in hell, His flesh in the sepulchre; but as respected His Godhead He was certainly also in paradise.
And therefore the soul of the thief, absolved from his by-gone crimes, and already in the blessed enjoyment of His grace, although it could not be everywhere as He was, yet could on that very day be also with Him in paradise, from which He, who is always everywhere, had not withdrawn. On this account, doubtless, it was not enough for Him to say, “I will that they also be where I am;” but He added, “with me.” For to be with Him is the chief good. For even the miserable can be where He is, since wheresoever any are, there is He also; but the blessed only are with Him, because it is only of Him that they can be blessed.
Was it not truly said to God, “If I ascend into heaven, You are there; and if I go down into hell, You are present?” or is not Christ after all that Wisdom of God which “penetrates everywhere because of its purity”? But the light shines in darkness and the darkness comprehends it not. And similarly, to take a kind of illustration from what is visible, although greatly unlike, as the blind man, even though he be where the light is, is yet not himself with the light, but is really absent from that which is present; so the unbeliever and profane, or even the believer and pious, because not yet competent to gaze on the light of wisdom, although he cannot be anywhere that Christ is not there likewise, yet is not himself with Christ, I mean in actual sight.
For we cannot doubt that the true believer is with Christ by faith; because in reference to this He says, “He that is not with me is against me.” But when He said to God the Father, “I will that they also whom You have given me be with me where I am,” He spoke exclusively of that sight wherein we shall see Him as He is.
Source: Tractates on the Gospel of John (New Advent)