Moses had anticipated that his people might not believe him (Exod 4:1), so God had provided signs so they would believe him (4:5, 8-9).
Yet now, even despite the signs, they certainly were not believing him. Moses had not wanted this mission anyway, and had obeyed only under this God’s duress (4:14-17, 24-26). Now he felt like God had let them all down.
Moses had been there only a little while, but now he complains that things had not gotten any better since he had been there (5:23). He observes that Pharaoh was mistreating God’s people—as if this were a new situation! Sometimes we get discouraged because God does not act on our schedule or because of suffering along the way.
Happily, God does not need to depend on our faith, contrary to what some well-meaning teachers today appear to insist. While God does respond to our cries to him (2:24) and especially to our dependent faith in him, there are also settings in which God initiates and calls and in these cases we may learn faith along the way. (The faith of Abraham in God’s promise seems to have been enough for God to fulfill this promise centuries later.) God will show himself faithful in fulfilling his plan—although not always our imagined version of it.