Chapter XVII. 21-23.
1. After the Lord Jesus had prayed for His disciples whom He had with Him at the time, and had conjoined with them others who were also His own, by saying, "Neither pray I for these alone, but for them also who shall believe on me through their word," as if we were inquiring what or wherefore He prayed for them, He straightway subjoined, "That they all may be one; as Thou, Father, [art] in me, and I in Thee, that they also may be one in us." And a little above, while still praying for the disciples alone who were then with Him, He said, "Holy Father, keep in Thine own name those whom Thou hast given me, that they may be one, as we are" (ver. 11). It is the same thing, therefore, that He now also prayed for in our behalf, as He did at that time in theirs, namely, that all--to wit, both we and they--may be one. And here we must take particular notice that the Lord did not say that we all may be one, but, "that they all may be one; as Thou Father, in me, and I in Thee" (where is to be understood are one, as is more clearly expressed afterwards); because He had also said before of the disciples who were with Him, "That they may be one, as we are." The Father, therefore, is in the Son, and the Son in the Father, in such a way as to be one, because they are of one substance; but while we may indeed be in them, we cannot be one with them; for they and we are not of one substance, in as far as the Son is God along with the Father. But in as far as He is man, He is of the same substance as we are. But at present He wished rather to call attention to that other statement which He made use of in another place, "I and the Father are one," [1761] where He intimated that His own nature was the same with that of the Father. And accordingly, though the Father and Son, or even the Holy Spirit, are in us, we must not suppose that they are of one nature with ourselves. And hence they are in us, or we are in them, in this sense, that they are one in their own nature, and we are one in ours. For they are in us, as God in His temple; but we are in them, as the creature in its Creator.
2. But then after saying, "That they also may be one in us," He added, "That the world may believe that Thou hast sent me." What does He mean by this? Is it that the world will then be brought to the faith, when we shall all be one in the Father and Son? Is not such a state the everlasting peace, and the reward of faith, rather than faith itself? For we shall be one not in order to our believing, but because we have believed. But although in this life, because of the common faith itself, all who believe in one are one according to the words of the apostle, "For ye are all one in Christ Jesus;" [1762] even thus we are one, not in order to our believing, but because we do believe. What, then, is meant by the words, "That they all may be one, that the world may believe"? This, doubtless, that the "all" are themselves the believing world. For those who shall be one are not of one class, and the world that is thereafter to believe on this very ground that these shall be one, of another; since it is perfectly certain that He says, "That they all may be one," of those of whom He had said before, "Neither pray I for these alone, but for those also who shall believe on me through their word," immediately adding as He does, "That they all may be one." And this "all," what is it but the world; not certainly that which is hostile, but that which is believing? For you see here that He who had said, "I pray not for the world," now prayeth for the world that it may believe. For there is a world whereof it is written, "That we might not be condemned with this world." [1763] For that world He prayeth not, for He is fully aware to what it is predestinated. And there is a world whereof it is written, "For the Son of man came not to condemn the world, but that the world through Him might be saved;" [1764] and hence the apostle also says, "God was in Christ, reconciling the world unto Himself." [1765] For this world it is that He prayeth, in saying, "That the world may believe that Thou hast sent me." For through this faith the world is reconciled unto God when it believes in the Christ whom God has sent. How, then, are we to understand Him when He says, "That they also may be one in us, that the world may believe that Thou hast sent me," but just in this way, that He did not assign the cause of the world believing to the fact that those others are one, as if it believed on the ground that it saw them to be one; for the world itself here consisteth of all who by their own believing become one; but in His prayer He said, "That the world may believe," just as in His prayer He also said, "That they all may be one;" and still further in the same prayer, "That they also may be one in us." For the words, "they all may be one," are equivalent to "the world may believe," since it is by believing that they become one, perfectly one; that is, those who, although one by nature, had ceased to be so by their mutual dissensions. In fine, if the verb which He uses, "I pray," be understood in the third clause, or rather, to make the whole fuller, be everywhere supplied, the explanation of this sentence will be all the clearer: I pray "that they all may be one; as Thou, Father, in me, and I in Thee;" I pray "that they also may be one in us;" I pray "that the world may believe that Thou hast sent me." And, mark, He added the words "in us" in order that we may know that our being made one in that love of unchanging faithfulness is to be attributed to the grace of God, and not to ourselves: just as the apostle, after saying, "For ye were at one time darkness, but now are ye light," that none might attribute the doing of this to themselves, added, "in the Lord." [1766]
3. Furthermore, our Saviour in thus praying to the Father showed Himself to be man; while He now also shows that He Himself, as being God along with the Father, doeth that which He prayeth for, when He says, "And the glory which Thou gavest me, I have given them." And what was that glory but immortality, which human nature was henceforth to receive in Him? For not even He Himself had as yet received it, but in His own customary way, on account of the absolute fixedness of predestination, He intimates what is future in verbs of the past tense, because being now on the point of being glorified, or in other words, raised up again by the Father, He Himself is going to raise us up to the same glory in the end. What we have here is similar to what He says elsewhere, "As the Father raiseth up the dead, and quickeneth them, even so the Son quickeneth whom He will." And "whom," but just the same as the Father? "For what things soever the Father doeth," not other things, but "these also doeth the Son," not in a different way, but "in like manner." [1767] And in this way He also raised up even His own self. For to this effect he said, "Destroy this temple, and in three days I will raise it up again." [1768] Accordingly the glory of immortality, which He says had been given Him by the Father, He must be also understood as having bestowed upon Himself, although He does not say it. For on this very account He more frequently says that the Father alone doeth, what He Himself also doeth along with the Father, that everything whatever He may attribute to Him of whom He is. But sometimes also He is silent about the Father, and says that He Himself doeth what He only doeth along with the Father: that we may thereby understand that the Son is not to be separated from the working of the Father, when He is silent about Himself, and ascribes some work or other to the Father; as, on the other hand, the Father is not separated from the working of the Son, when the Son is said, without any mention being made of [the Father] Himself, to be doing some work in which nevertheless both are equally engaged. When, therefore, in some work of the Father, the Son says nothing of His own working, He commends humility, that He may become the source of sounder health to us; but when, in turn, in the case of some work of His own, He says nothing of the working of the Father, He commends His own equality, that we may not suppose Him to be inferior. In this way, then, and in this passage, He neither estranges Himself from the Father's working, although He has said, "The glory which Thou gavest me;" for He also gave it to Himself: nor does He estrange the Father from His own working, although saying, "I have given to them;" for the Father also gave it to them. For the works not only of the Father and the Son, but also of the Holy Spirit, are inseparable. But just as, because of His praying the Father in behalf of all His people, it was His own pleasure that this should be done, "that they all may be one;" so also on the ground of His own beneficence, as expressed in the words, "The glory which Thou gavest me, I have given them," the doing of that was none the less His pleasure; for He immediately added, "That they may be one, as we also are one."
4. And then He added: "I in them, and Thou in me, that they may be made perfect in one." Here He briefly intimated Himself as the Mediator between God and men. Nor was this said in any such way as if the Father were not in us, or we were not in the Father; since He had also said in another place, "We will come unto him, and make our abode with him;" [1769] and a little before in this present passage He had not said, "I in them and Thou in me," as He said now; or, They in me, and I in Thee; but, "Thou in me, and I in Thee, and they in us." Accordingly, when He now says, "I in them, and Thou in me," the words take this form in reference to the person of the Mediator, like that other expression used by the apostle, "Ye are Christ's, and Christ is God's." [1770] But in adding, "That they may be made perfect in one," He showed that the reconciliation, which is effected by the Mediator, is carried to the very length of bringing us to the enjoyment of that perfect blessedness, which is thenceforth incapable of further addition. Hence the words that follow, "That the world may know that Thou hast sent me," are not, I think, to be taken as if He had again said, "That the world may believe;" for sometimes, to know, is also used in the same sense as to believe, as it is in the words He uttered some time before: "And they have known truly that I came out from Thee, and they have believed that Thou didst send me." He expressed the same thing by the later words, "they have believed," as He had done by the earlier, "they have known." But inasmuch as He here speaks of the consummation, the knowledge must be taken for such, as it shall then be by sight, and not, as it now is, by faith. For an order seems to have been preserved in reference to what He said a little before, "that the world may believe;" while here it is, "that the world may know." For although He said there, "that they all may be one," and "may be one in us," yet He did not say, "they may be made perfect in one," and so subjoined the words, "that the world may believe that Thou hast sent me;" but here He said, "That they may be made perfect in one," and then added, not, "that the world may believe," but, "that the world may know that Thou hast sent me." For so long as we believe what we do not see, we are not yet made perfect, as we shall be when we have merited the sight of that which we believe. Most correctly, therefore, did He say in that previous place, "That the world may believe," and here "That the world may know;" yet both there and here, "that Thou hast sent me;" that we may know, so far as belongs to the inseparable love of the Father and the Son, that at present we only believe what we are on the way, by believing, to know. And had He said, That they may know that Thou hast sent me, it would be just of the same force as what He actually does say, "that the world may know." For they are the world that abideth not in enmity, as doth the world that is foreordained to damnation; but one that out of an enemy has been transformed into a friend, and on whose account "God was in Christ reconciling the world unto Himself." Therefore said He, "I in them, and Thou in me;" as if He had said, I in those to whom Thou hast sent me; and Thou in me, reconciling the world unto Thyself through me.