Jamieson, Fausset and Brown on Jonah 1:7

7. cast lots--God sometimes sanctioned this mode of deciding in difficult cases. Compare the similar instance of Achan, whose guilt involved Israel in suffering, until God revealed the offender, probably by the casting of lots (Pr 16:33; Ac 1:26). Primitive tradition and natural conscience led even the heathen to believe that one guilty man involves all his associates, though innocent, in punishment. So Cicero [The Nature of the Gods, 3.37] mentions that the mariners sailing with Diagoras, an atheist, attributed a storm that overtook them to his presence in the ship (compare Horace's Odes, 3.2.26).