Exodus 4:18 - The Popular Commentary by Paul E. Kretzmann

And Moses went and returned to Jethro, his father-in-law, and said unto him, Let me go, I pray thee, and return unto my brethren which are in Egypt, and see whether they be yet alive. The faithfulness, the sense of duty in Moses would not have permitted him to leave the flocks in the wilderness and to go to Egypt without leave-taking, even for a short while. He told Jethro as much of the truth as the latter needed to know at that time, for he would hardly have found a complete understanding of his object and of the divine revelation in the home of his relatives by marriage. And Jethro said to Moses, Go in peace.