Exodus 2:22
21 Moses agreed to stay with the man, and he gave his daughter Zipporah to Moses in marriage. 22 When she bore a son, Moses named him Gershom, for he said, “I have become a resident foreigner in a foreign land.” 23 During that long period of time the king of Egypt died, and the Israelites groaned because of the slave labor. They cried out, and their desperate cry because of their slave labor went up to God.
Exodus 18:3
2 Jethro, Moses’ father-in-law, took Moses’ wife Zipporah after he had sent her back, 3 and her two sons, one of whom was named Gershom (for Moses had said, “I have been a foreigner in a foreign land”) 4 and the other Eliezer (for Moses had said, “The God of my father has been my help and delivered me from the sword of Pharaoh”). 5 Jethro, Moses’ father-in-law, together with Moses’ sons and his wife, came to Moses in the wilderness where he was camping by the mountain of God.
Notes and References
"... Exodus 19:1-5 ... The explanation of the name Gershom here in E is a doublet of Exodus 2:22, which is J. The existence of a second son, Eliezer, is reported only here in E, not in J. In J there was only one son. Also, in J Moses took his son and Zipporah with him to Egypt. But now, in E, Jethro shows up bringing Zipporah and their sons, who have been in Midian all along. The words “after her being sent off” appear to have been added by the Redactor of J and E to solve this contradiction ..."
Friedman, Richard Elliott The Bible with Sources Revealed: A New View Into the Five Books of Moses (p. 150) Harper San Francisco, 2005