Charles Ellicott Commentary Jonah 1:7

"And they said every one to his fellow, Come, and let us cast lots, that we may know for whose cause this evil is upon us. So they cast lots, and the lot fell upon Jonah." — Jonah 1:7 (ASV)

Come, and let us cast lots.—We are to suppose that Jonah, coming on deck in compliance with the captain’s request, adds his prayers to those of the crew. Finding all their efforts ineffective, the sailors propose to resort to the ancient custom of casting lots to discover the guilty person against whom the deities are so enraged. Classical authors as well as the Bible (Compare Joshua 7:14 and following; 1 Samuel 14:36–46) offer many illustrations of the belief that the presence of an impious man would involve all who shared his company in indiscriminate ruin. Naturally, this feeling expressed itself most strongly at sea.

“Who drags Eleusis’ rite today,
That man shall never share my home
Or join my voyage; roofs give way,
And boats are wrecked; true men and thieves
Neglected Justice often confounds.”

Horace, Od. iii. 2, 26-30 (Conington's translation).

Compare the story told by Cicero of Diagoras (de Nat. Deor. 3:3). Aeschylus, Sept. cont. Theb. 601-604. Sophocles, Ant. 372.