This can be stated in active form. Alternate translation: "when he heard a voice come from the Majestic Glory" or "when he heard the voice of the Majestic Glory speak to him" or "when the Majestic Glory spoke to him" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Peter refers to God in terms of his glory. This is a euphemism that avoids using God's name, out of reverence for him. Alternate translation: "God, the Supreme Glory, saying" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-euphemism]])