John 12:30 - Ellicott's Commentary On The Whole Bible

This voice came not because of me, but for your sakes. — More exactly, not for My sake did this voice come, but for your sakes. These words are an answer to the thoughts, spoken and unspoken, of the multitude. Jesus Himself knew that the Father heareth Him always, but this answer is a sign to others. (Comp. John 11:41-42.) He calls it a voice in answer to those who said it thundered, or that an angel had spoken. There was that, then, which seemed to them but the thunder’s sound or an angel’s word, which, coming in answer to His prayer and after His teaching. should have been, to ears ready to hear and minds willing to receive, the voice of God witnessing to the mission of His Son.