Luke 5:4

‘And when he had finished speaking, he said to Simon, “Put out into the deep, and let down your nets for a draught.” '

Then when He had finished preaching He turned to Simon Peter and said, “Put out into the deep, and let down your nets for a draught.” The prophetic command probably made Peter give a grim smile, and give his partner a look. No one knew better than they that there were no fish to be had. If they could not be found at night when it was dark, this time of the morning when the sun was shining on the water would be hopeless. But his calibre is revealed in his obedience to the Prophet. If He told him to do something, then he would do it. It could do no harm even though they were very tired, and it would please Him, and possibly teach Him a lesson about fish.