19. They were terrified. The other Evangelists explain the cause of that fear to have been, that they thought that it was an apparition, (Matthew 14:26; Mark 6:49.) Now it is impossible not to be seized with consternation and dread, when an apparition is presented before our eyes; for we conclude that it is either some imposture of Satan, or some bad omen which God sends us. Besides, John here holds out to us, as in a mirror, what kind of knowledge of Christ we may obtain without the word, and what advantage may be reaped from that knowledge. For if he present a simple demonstration of his divinity, we immediately fall into our imaginations, and every person forms an idol for himself instead of Christ. After we have thus wandered in our understanding, this is immediately followed by trembling and a confused terror of heart. But when he begins to speak, we then obtain from his voice clear and solid knowledge, and then also joy and delightful peace dawn upon our minds. For there is great weight in these words: