(Tr. li. 8) Listen we to the voice of the corner stone: And Jesus answered them, saying, The hour is come, that the Son of man should be glorified. Did He think Himself glorified, because the Gentiles wished to see? No. But He saw that after His passion and resurrection, the Gentiles in all lands would believe on Him; and took occasion from this request of some Gentiles to see Him, to announce the approaching fulness of the Gentiles, for that the hour of His being glorified was now at hand, and that after He was glorified in the heavens, the Gentiles would believe; according to the passage in the Psalm, Set up Thyself, O God, above the heavens, and Thy glory above all the earth. (Ps. 56, and 107) But it was necessary that His exaltation and glory should be preceded by His humiliation and passion; wherefore He says, Verily, verily, I say unto you, Except a corn of wheat fall into they round and die, it abideth alone: but if it die, it bringeth forth much fruit. That corn was He; to be mortified in the unbelief of the Jews, to be multiplied in the faith of the Gentiles.
Source: Catena Aurea by Aquinas