John 12:28

Father glorify thy name. There came therefore a voice out of heaven, saying, I have both glorified it, and will glorify it again.

Three times God spoke out of heaven during the ministry of Jesus: here, at the baptism, and at the transfiguration (Mark 1:11; 9:7, and parallels). The Jews are said to have regarded thunder as an echo of the voice of God; but, "In all four Gospels, it is no mere echo of God's voice that is heard, but the direct speaking of the Father to the Son."[17]

Glorify thy name ... Offered in the emotional tension arising from Jesus' consciousness that his "hour" was at hand, this prayer is surprising in that it has no petition for himself, but only for the glory of the Father's name.

I have both glorified it, and will glorify it again ...

Christ had glorified God by his ministry among the Jews, and he was now to glorify him by his death for all men, and by the gradual spread of the gospel among all nations.[18]

[17] Alan Richardson, op. cit., p. 153.

[18] Alvah Hovey, op. cit., p. 255.