1 The Lord Jesus raises up His people to a great hope, than which there could not possibly be a greater. Listen and rejoice in hope, that, since the present is not a life to be loved, but to be tolerated, you may have the power of patient endurance amid all its tribulation. Listen, I say, and weigh well to what it is that our hopes are exalted. Christ Jesus says, The Son of God, the Only-begotten, who is co-eternal and equal with the Father, says: He, who for our sakes became man, but became not, like every man besides, a liar, says: the Way, the Life, the Truth says: He who overcame the world, says of those for whom He overcame it: listen, believe, hope, desire what He says: “Father,” He says, “I will that they also whom You have given me be with me where I am.”
Who are these who He says were given Him by the Father? Are they not those of whom He says in another place, “No man comes unto me, unless the Father, who has sent me, draw him”? We already know if we have made any beneficial progress in this Gospel, how it is that the things which He says the Father does, He Himself does likewise along with the Father. They are those, therefore, whom He has received from the Father, whom He Himself has also chosen out of the world, and chosen that they may be no more of the world, even as He also is not of the world; and yet that they also may be a world that believes and knows that Christ has been sent by God the Father that the world might be delivered from the world, and so, as a world that was to be reconciled unto God, might not be condemned with the world that lies in enmity.
For so He says in the beginning of this prayer: “You have given Him power over all flesh,” that is, over every man, “that He should give eternal life to as many as You have given Him.” Here He makes it clear that He has indeed received power over all men, that, as the future Judge of quick and dead, He may deliver whom He pleases, and condemn whom He pleases; but that these were given Him that to all of them He should give eternal life. For so He says: “That He should give eternal life to as many as You have given Him.”
Accordingly they were not given Him that from them He should withhold eternal life; although over them also the power has been given Him, inasmuch as He has received it over all flesh, in other words, over every man. In this way the world that has been reconciled will be delivered from the hostile world, when He puts into exercise His power over it, to send it away into death eternal; but the other He makes His own that He may give it everlasting life. Accordingly, to every one, without fail, of His own sheep the Good Shepherd, as to every one of His members the great Head, has promised this reward, that where He is, there also we shall be with Him; nor can that be otherwise which the omnipotent Son declared to be His will to the omnipotent Father.
For there also is the Holy Spirit, equally eternal, equally God, the one Spirit of the two, the substance of the will of both. For the words that we read of Him as uttering on the eve of His passion, “Yet not, Father, as I will, but as You will,” as if the Father has or had one will, and the Son another, are the echo of our infirmity, however faith-pervaded, which our Head transfigured in His own person, when He likewise bare our iniquities. But that the will of the Father and the Son is one, of both of whom also there is but one Spirit, by including whom we come to the knowledge of the Trinity, let piety believe, even though our infirmity meanwhile permits us not to understand.
Source: Tractates on the Gospel of John (New Advent)