Adam Clarke on John 12:30

This voice came not because of me, but for your sakes - Probably meaning those Greeks who had been brought to him by Philip and Andrew. The Jews had frequent opportunities of seeing his miracles, and of being convinced that he was the Messiah; but these Greeks, who were to be a first fruits of the Gentiles, had never any such opportunity. For their sakes, therefore, to confirm them in the faith, this miraculous voice appears to have come from heaven.