Q. In the Book of Jonah, why do the sailors ask Jonah what his occupation is?
A. The sailors feel that Jonah may have brought shame upon himself and calamity upon the ship because of some transgression connected with his occupation.
Rashi says that Jonah may have been negligent in his work, whatever his occupation. Radak suggests that Jonah may be engaged in an occupation that operates on deceit and fraud.
Metzudat David urges Jonah to repent before it is too late: “If your sin concerns unjust monetary gain, return it to the person you cheated”.