Exodus 18:1

Exo 18:1 When Jethro, the priest of Midian, Moses’ father in law, heard of all that God had done for Moses, and for Israel his people, [and] that the LORD had brought Israel out of Egypt;

Ver. 1. Heard of all. ] And thereby was converted, say the Rabbis, being the first proselyte to the Jewish Church that we read of in the Scripture.