In Exodus 4, Moses expressed doubt about his mission to deliver the children of Israel from slavery in Egypt, worrying that the Israelites wouldn’t believe that God truly appeared to him. In response, God equipped Moses with three miraculous signs to validate his commission:

First, Moses’s staff transformed into a snake when he threw it to the ground and then turned back into a staff when he picked it up.
Second, his hand became leprous when he placed inside his cloak, and then it was restored to health when he did it again.
Third, God told him that, if those two signs weren’t enough, he could pour water from the river on the ground and it would turn into blood.

These signs were given as proof to persuade the Israelites that Moses had truly encountered the God of their ancestors.

Despite receiving those powerful signs, Moses continued to resist his calling, pleading that he wasn’t an eloquent speaker and had never been. God firmly countered that excuse, reminding Moses that it was He who made the human mouth and that He would teach Moses what to say. Moses made one final plea, simply asking God to send someone else. This angered the LORD, but He provided a solution: Moses’s brother Aaron (a capable speaker who was already on his way to meet him) would serve as Moses’s mouthpiece. God would instruct Moses, Moses would instruct Aaron, and Aaron would speak to the people on their behalf.

With his objections resolved, Moses returned to his father-in-law Jethro and asked permission to go back to Egypt to see whether his people were still alive.

God reassured Moses that the men in Egypt who had wanted to kill him were now dead. Moses then set out with his wife Zipporah and their sons, carrying the staff of God. God gave Moses final instructions for the confrontation with Pharaoh — including the striking message that Israel was God’s firstborn son — and that, if Pharaoh refused to let Israel go, God would strike down Pharaoh’s own firstborn son (a foreshadowing of the final plague to come).

Then, something unusual occurred at a lodging place along the journey. The LORD met Moses and “sought to kill him.” Zipporah acted quickly, circumcising their son and casting the foreskin at Moses’s feet, after which God let Moses go. This event is generally understood as a warning that Moses, who was to lead God’s covenant people, couldn’t himself be in violation of the covenant sign of circumcision within his own household.

At the close of Exodus 4, Aaron met Moses at the mountain of God, and they returned to Egypt together. Aaron spoke to the Israelite elders and performed the miraculous signs before the people, and the Israelites believed. When they heard that God had seen their suffering and was moving to deliver them, they bowed down and worshipped.