How do we know the accounts of the Transfiguration are true?

The validity of the Transfiguration accounts can be traced back to the consistent testimony among the Gospel writers and the first-hand experiences of Peter, James, and John. Notably, in 2 Peter 1:16-18, Peter asserts, 'We have not followed cunningly devised fables, but were eyewitnesses of His majesty.' The differences in detail among the accounts—such as the mention of 'after six days' in Matthew and Mark versus 'about eight days' in Luke—are reconciled when understanding that both accounts are true and complement each other rather than contradicting. Additionally, the event’s significance as a divine revelation supports its legitimacy within the greater narrative of Christ's mission, manifesting His glory to empower the disciples’ faith in light of His imminent death and resurrection.