Charles Ellicott Commentary John 6:19

"When therefore they had rowed about five and twenty or thirty furlongs, they behold Jesus walking on the sea, and drawing nigh unto the boat: and they were afraid." — John 6:19 (ASV)

Five and twenty or thirty furlongs—that is, about half their voyage. Josephus describes the lake as forty furlongs wide (Wars, iii. 10, § 7). Compare to Matthew 14:25.