A.T. Robertson Commentary John 6:20

"But he saith unto them, It is I; be not afraid." — John 6:20 (ASV)

Be not afraid (μη φοβεισθε). Prohibition with μη and present middle imperative of φοβεομα. So in Mr 6:50 (Matthew 14:27). John does not tell that the disciples thought Jesus was an apparition (Matthew 14:26), nor does he give the account of Peter walking on the water (Matthew 14:28–31).