The sea was tossed by a great wind blowing.

 Let us reconstruct the story. After the feeding of the five thousand and the attempt to make him king, Jesus slipped away to the hills alone. The day wore on. It came to the time which the Jews described as "the second evening," the time between the twilight and the dark. Jesus had still not arrived. We must not think that the disciples were forgetful or discourteous in leaving Jesus behind, for, as Mark tells the story, Jesus sent them on ahead ( Mark 6:45), while he persuaded the crowds to go home. Doubtless it was his intention to walk round the head of the lake while they rowed across and to rejoin them in Capernaum. 