The prophet like Moses
Peter quotes Moses' promise that God would raise up a prophet like him and that the people must listen to Him; Stephen later repeats the same promise while recounting Moses' ministry.
The LORD your God will raise up for you a prophet like me from among your brothers. You must listen to him. This is what you asked of the LORD your God at Horeb on the day of the assembly, when you said, “Let us not hear the voice of the LORD our God or see this great fire anymore, so that we will not die!” Then the LORD said to me, “They have spoken well. I will raise up for them a prophet like you from among their brothers. I will put My words in his mouth, and he will tell them everything I command him. And I will hold accountable anyone who does not listen to My words that the prophet speaks in My name.
Deuteronomy 18:15-19 promises a prophet from among Israel's brothers who will speak God's words; Acts 3:22-23 quotes that promise in Peter's sermon about Jesus, and Acts 7:37 repeats it in Stephen's address.