cleverly devised fables: The false teachers were probably claiming that the message about Christ’s return was only a helpful story and not a true event.
we were eyewitnesses of His majesty: This refers to the transfiguration of Jesus (Matthew 17:1–9; Mark 9:2–8; Luke 9:28–36). The transfiguration was a moment when the appearance of Jesus changed in a bright and glorious way. At that moment, Jesus was revealed as the glorious King, which pointed to his future return. Peter’s confidence did not come from human guesses but from what he personally saw.