John Calvin Commentary John 6:17

"and they entered into a boat, and were going over the sea unto Capernaum. And it was now dark, and Jesus had not yet come to them." — John 6:17 (ASV)

It was now dark. John omits many circumstances that the other Evangelists include. For example, they record that for several hours the disciples struggled against an opposing wind, as it is likely that the storm arose immediately after night began to fall. These Evangelists also tell us that Christ did not appear to His disciples until about the fourth watch of the night (Matthew 14:28; Mark 6:48). Those who speculate that they were still about the middle of the lake when Christ appeared to them (because John says that they had then advanced about twenty-five or thirty furlongs) are mistaken in supposing that they had sailed to the farther or opposite shore; for Bethsaida, near which town Luke tells us the miracle was performed (Luke 9:10), and Capernaum, which the ship reached (John 6:16), were located on the same coast.

Pliny, in his fifth book, states that this lake was six miles in width and sixteen in length. Josephus (in the third book of the Wars of the Jews) assigns to it a length of one hundred furlongs and a width of forty; and as eight furlongs make one mile, we can easily infer how little the one description differs from the other. Regarding this particular sailing, my opinion is that they did not cover such a great distance by direct sailing, but by being driven about by the tempest. Be that as it may, the Evangelist intended to show that when Christ appeared to them, they were in the utmost danger. It may seem strange that the disciples should be tormented in this way, while others sailed without anything to disturb them; but in this way the Lord often causes His people to fall into alarming dangers, so that they may more clearly and intimately recognize Him in their deliverance.