ISB ~ 2 Peter 1 v16

eyewitnesses:The apostles Peter, James, and John accompanied Jesus on the mountain of Transfiguration (Mt 17:18). Their testimony to Christ was therefore based on the facts of history and firsthand experience, quite unlike the imaginative tales spun by the false teachers denounced in the letter (2 Pet 2:3). This past revelation of Christ’s glory is considered a preview of the future revelation of Christ’s glory at his Second Coming (CCC 554-55).