The shipmaster - Either the captain or the pilot.
Arise, call upon thy God - He supposed that Jonah had his god, as well as they had theirs; and that, as the danger was imminent, every man should use the influence he had, as they were all equally involved in it.
What meanest thou? - or rather, “what aileth thee?” (literally “what is to thee?”) The shipmaster speaks of it (as it was) as a sort of disease, that he should be thus asleep in the common peril. “The shipmaster,” charged, as he by office was, with the common weal of those on board, would, in the common peril, have one common prayer. It was the prophet‘s office to call the pagan to prayers and to calling upon God. God reproved the Scribes and Pharisees by the mouth of the children who “cried Hosanna” Matthew 21:15; Jonah by the shipmaster; David by Abigail; 1 Samuel 25:32-34; Naaman by his servants. Now too he reproves worldly priests by the devotion of laymen, sceptic intellect by the simplicity of faith.
If so be that God will think upon us - , (literally “for us”) i. e., for good; as David says, Psalm 40:17. “I am poor and needy, the Lord thinketh upon” (literally “for”) “me.” Their calling upon their own gods had failed them. Perhaps the shipmaster had seen something special about Jonah, his manner, or his prophet‘s garb. He does not only call Jonah‘s God, “thy” God, as Darius says to Daniel “thy God” Daniel 6:20, but also “the God,” acknowledging the God whom Jonah worshiped, to be “the God.” It is not any pagan prayer which he asks Jonah to offer. It is the prayer of the creature in its need to God who can help; but knowing its own ill-desert, and the separation between itself and God, it knows not whether He will help it. So David says Psalm 25:7, “Remember not the sins of my youth nor my transgressions; according to Thy mercy remember Thou me for Thy goodness‘ sake, O Lord.”
“The shipmaster knew from experience, that it was no common storm, that the surges were an infliction borne down from God, and above human skill, and that there was no good in the master‘s skill. For the state of things needed another Master who ordereth the heavens, and craved the guidance from on high. So then they too left oars, sails, cables, gave their hands rest from rowing, and stretched them to heaven and called on God.”