2 Peter 1:18
And this voice which came from heaven we heard, when we were with him in the holy mount.
Cross-reference
Matthew 17:6
Historical context
Matthew 17:6 records the disciples' terrified reaction to the same voice—confirming the historical event Peter recounts here.
Deuteronomy 4:12
Parallel
Deuteronomy 4:12 recounts God speaking from fire with a voice—directly parallels the voice from heaven on the mountain in 2 Peter.
Matthew 17:1
Parallel
Matthew 17:1 records the same transfiguration event — the high mountain where Peter heard the heavenly voice.
Luke 9:35
Parallel
Luke 9:35 records the same transfiguration voice — 'This is my Son' — confirming the event Peter describes.