It took real guts to stand up in front of the Jewish high council and quote Jewish history. Of course they already knew it, but they didn’t know it in light of Jesus. This was Stephen’s mission: to help them understand how their prior knowledge of God fit into the new work he was doing with Jesus. Plus, the accusation from the lying witness was that Jesus came to change the customs given by Moses. Indeed that was true, but not without context. Hopefully, some present in that room understood how the picture fit together.