Acts 4:13–31 (ESV)

13 Now when they saw the boldness of Peter and John, and perceived that they were uneducated, common men, they were astonished. And they recognized that they had been with Jesus.

Having been arrested and testified to Jesus before the Sanhedrin (Acts 4:1–12), the apostles will now hear the response from the Jewish council (Acts 4:16–17), after which they will publicly voice their unwillingness to conform (Acts 4:18–20).