The sailors saw all the signs, the miracles, and the great wonders which the Holy One, blessed be He, did unto Jonah, and they stood and they cast away every one his God, as it is said, "They that regard lying vanities forsake their own shame" (Jonah 2:8). They returned to Joppa and went up to Jerusalem and circumcised the flesh of their foreskins, as it is said, "And the men feared the Lord exceedingly; and they offered a sacrifice unto the Lord" (Jonah 1:16).
Did they offer sacrifice? But this (sacrifice) refers to the blood of the covenant of circumcision, which is like the blood of a sacrifice. And they made vows every one to bring his children and all belonging to him to the God of Jonah; and they made vows and performed them, and concerning them it says, "Upon the proselytes, the proselytes of righteousness."