John Chrysostom — as excerpted in the Catena Aurea on John 6:15-21

“(Hom. xlii. 3) See what the belly can do. They care no more for the violation of the Sabbath; all their zeal for God is fled, now that their bellies are filled: Christ has become a Prophet, and they wish to enthrone Him as king. But Christ makes His escape; to teach us to despise the dignities of the world. He dismisses His disciples, and goes up into the mountain.— (Hom. xliii. 1). These, when their Master had left them, went down in the evening to the sea; as we read; And when even was now come, His disciples went down unto the sea. They waited till evening, thinking He would come to them; and then, as He did not come, delayed no longer searching for Him, but in the ardour of love, entered into a ship, and went over the sea toward Capernaum. They went to Capernaum thinking they should find Him there.”