God’s signs had put the fear of God in Moses, enough to make him obey. But Moses’s obedience is still half-hearted, and (as will become obvious in the next lesson) incomplete.
After receiving this astonishing commission and these signs from God, Moses returns to his father-in-law and asks permission to go visit his siblings in Egypt (Exod 4:18). Moses owes respect to his father-in-law (e.g., 18:7), and it was respectful not to take leave of one’s family service prematurely (Jethro is a much friendlier in-law to Moses than was Laban the Aramean to Jacob; Gen 31:27-31). Did Jethro by now (vs. Exod 2:19) understand that Moses was an Israelite rather than an Egyptian? It may not have made a difference, but certainly by Exodus 18:1 Jethro knows, so it is not unlikely that he understood this earlier.
While Moses dare not disobey this God who called him, however, he says nothing to Jethro about God’s commission. He is still half-hearted, not knowing what will happen in Egypt. He says he wants to go to see if his relatives are alive (4:18). (His concern as to whether his relatives remain alive may also be legitimate; Moses is about eighty in this narrative, and his brother and sister are even older; 7:7. Many Israelites Moses knew may have by now passed away.)
Possibly a more urgent concern regarding survivors of his generation is whether those who wanted him killed are still alive. Thus, before Moses leaves Midian, the Lord again calls him to return to Egypt, informing him those who had sought his life are now dead (4:19).
Yet the Lord does not make Moses’s calling easier at this point by watering down what Moses will face. In fact, he warns him up front what he is in for. God will harden Pharaoh’s heart (4:21) and Moses is to warn Pharaoh that God will kill Pharaoh’s son for his disobedience (4:23). One needs little imagination to envision how Pharaoh, who fancied himself divine, would take an ultimatum and threat from the god of his slaves.
What God calls us to do often leads through serious hardships. Our hearts may not even be in his calling at first. That can be true whether we are thinking of God’s calling for all of us to make disciples, or of more specific aspects of our calling. But God has a plan, and one dare not disregard God’s commands—as Moses will soon discover. Confronting Pharaoh may be dangerous, but disobeying God nearly gets Moses killed (4:24).