I have glorified thee. His reason for saying this is, that God had been made known to the world both by the doctrine of Christ, and by his miracles; and the glory of God is, when we know what he is. When he adds, I have finished the work which thou gavest me to do, he means that he has completed the whole course of his calling; for the full time was come when he ought to be received into the heavenly glory Nor does he speak only of the office of teaching, but includes also the other parts of his ministry; for, though the chief part of it still remained to be accomplished, namely, the sacrifice of death, by which he was to take away the iniquities of us all, yet, as the hour of his death was already at hand, he speaks as if he had already endured it. The amount of his request, therefore, is that the Father would put him in possession of the kingdom; since, having completed his course, nothing more remained for him to do, than to display, by the power of the Spirit, the fruit and efficacy of all that he had done on earth by the command of his Father, according to the saying of Paul, He humbled and annihilated himself, [1] by taking the form of a servant. Therefore God hath highly exalted him, and given him a name which is above every name, (Philippians 2:7, 10.)

Footnotes

1 - "It s'est humilie et antanti soy-mesme."

Have glorified thee - In my instructions and life. See his discourses everywhere, the whole tendency of which is to put honor on God.
I have finished the work - Compare John 19:30. When he says "I have finished," he probably means to include also his death. All the preparations for that death were made. He had preached to the Jews; he had given them full proof that he was the Messiah; he had collected his disciples; he had taught them the nature of his religion; he had given them his parting counsel, and there was nothing remaining to be done but to return to God. We see here that Jesus was careful that his great and important work should be done before his dying hour. He did not postpone it to be performed just as he was leaving the world. So completely had he done his work, that even before his death he could I say, "I have finished the work." How happy would it be if men would imitate his example, and not leave their great work of life to be done on a dying bed? Christians should have their work accomplished, and when that hour approaches, have nothing to do but to die, and return to their Father in heaven.

I have glorified thee - Our Lord, considering himself as already sacrificed for the sin of the world, speaks of having completed the work which God had given him to do: and he looks forward to that time when, through the preaching of his Gospel, his sacrifice should be acknowledged, and the true God should be known and worshipped by the whole world.

I have glorified thee on the earth,.... This is made use of as a reason and argument, why the Father should glorify him: Christ glorified his Father personally, as he held forth and expressed the glory of his person; and verbally, by ascribing, on all occasions, praise and glory to him; and really, or by deeds, and that by various ways: as in and by his ministry; by asserting he had his mission, qualifications, and doctrine, from him as a prophet; his principal work was to declare his Father's mind and will, his love and grace; nor did he seek his own, but his Father's glory: and by his miracles: for though these were proofs of his deity and Messiahship, and displays of his own glory; yet the glory of his Father, especially of his power, was eminently seen in them, for he referred them to him; and these were often the means of men's glorifying the God of Israel: and by his whole life and conversation, which was entirely according to the will of God; and every action of it was directed to his glory; particularly he glorified him by his early regard to his will, and the business he sent him about; by his zeal for his Father's house; and by the exercise of the various graces of faith, hope, and love upon him: and as by his life, so at his death, even all the while he was "on the earth"; where God had been dishonoured by the sin of men; where Christ now was debased in human nature, and even that was for the glory of God; and this is said in distinction from heaven, where God is glorified by the angels, and where Christ would shortly be glorified in his human nature:
I have finished the work which thou gavest me to do; by "the work" is meant obedience to the will of God; the destruction of all spiritual enemies, as sin, Satan, the world, and death; and the redemption and salvation of his people, which was "given" him to do: he did not take it upon himself, but being called to it he readily accepted of it; it was appointed, and cut out for him, in the council and covenant of grace; he was thoroughly acquainted with it; and though it was difficult, it was pleasant and delightful to him; nor did he leave it till he could say it is "finished"; as it was by himself alone, without the help of man; and is so complete that nothing can be added to it; and so firmly done, that it cannot be unravelled by men and devils: he speaks of it as done, because the time was come to finish it, and he was sure of the accomplishment of it.

I have glorified thee on the earth--rather, "I glorified" (for the thing is conceived as now past).
I have finished--I finished.
the work which thou gavest me to do--It is very important to preserve in the translation the past tense, used in the original, otherwise it might be thought that the work already "finished" was only what He had done before uttering that prayer; whereas it will be observed that our Lord speaks throughout as already beyond this present scene (John 17:12, &c.), and so must be supposed to include in His "finished work" the "decease which He was to accomplish at Jerusalem."

I have glorified thee on the earth. He had done this because he could say, "I have finished the work that thou gavest me to do."

I have finished the work - Thus have I glorified thee, laying the foundation of thy kingdom on earth.