4 “Then came there a voice from heaven, [saying], I have both glorified it, and will glorify it again.” “I have both glorified it,” before I created the world, “and I will glorify it again,” when He shall rise from the dead and ascend into heaven. It may also be otherwise understood. “I have both glorified it,”— when He was born of the Virgin, when He exercised miraculous powers; when the Magi, guided by a star in the heavens, bowed in adoration before Him; when He was recognized by saints filled with the Holy Spirit; when He was openly proclaimed by the descent of the Spirit in the form of a dove, and pointed out by the voice that sounded from heaven; when He was transfigured on the mount; when He wrought many miracles, cured and cleansed multitudes, fed so vast a number with a very few loaves, commanded the winds and the waves, and raised the dead—“and I will glorify it again;” when He shall rise from the dead; when death shall have no longer dominion over Him; and when He shall be exalted over the heavens as God, and His glory over all the earth.
Source: Tractates on the Gospel of John (New Advent)