Jamieson, Fausset and Brown on Exodus 2:16-22

16-22. the priest of Midian--or, "prince of Midian." As the officers were usually conjoined, he was the ruler also of the people called Cushites or Ethiopians, and like many other chiefs of pastoral people in that early age, he still retained the faith and worship of the true God.

seven daughters--were shepherdesses to whom Moses was favorably introduced by an act of courtesy and courage in protecting them from the rude shepherds of some neighboring tribe at a well. He afterwards formed a close and permanent alliance with this family by marrying one of the daughters, Zipporah, "a little bird," called a Cushite or Ethiopian (Nu 12:1), and whom Moses doubtless obtained in the manner of Jacob by service [see Ex 3:1]. He had by her two sons, whose names were, according to common practice, commemorative of incidents in the family history [Ex 18:3, 4].