Exodus 18:4

and the name of the other was Eliezer (God my Helper ); for the God of my father, said he, was mine Help, and delivered me from the sword of Pharaoh. These two sons had been born to Moses in the land of Midian while he lived with his father-in-law Reuel, Exodus 2:22; Exodus 4:25. It seems that Moses had agreed with his wife that she should meet him when he would return with the children of Israel; for he had had, even at that time, the promise of the Lord that Israel would be delivered out of the house of bondage, and that they would worship God on Mount Horeb. As the news of the mighty deeds of God, therefore, went out into the surrounding countries, Jethro also heard it and acted accordingly.