5 “The people therefore that stood by, and heard it, said that it thundered: others said, An angel spoke to Him. Jesus answered and said, This voice came not because of me, but for your sakes.” He thereby showed that the voice made no intimation to Him of what He already knew, but to those who needed the information. And just as that voice was uttered by God, not on His account, but on that of others, so His soul was troubled, not on His own account, but voluntarily for the sake of others.
Source: Tractates on the Gospel of John (New Advent)