Why did Peter and John go to the temple to pray in Acts 3?

Peter and John went to the temple to pray because they had no concept of the Church Age. They were still under Judaism's legal system and remained an extension of Christ's earthly ministry, performing miracles no different from what Christ had done for three years.

Les teaches that when Peter and John go up to the temple to pray, it is because they had no concept of what we call the Church Age. They were still under the legal system of Judaism and an extension of Christ's earthly ministry. The miracle they perform in Acts is nothing different than what Christ had been doing for three years. This connects to the mystery that was hid in God from the beginning of the age, kept secret until God was ready to reveal it.

Acts 3

What did Peter and John understand about Jesus in Acts 3?

In Acts 3, Peter and John understood that Jesus was the Messiah, the Son of God, and that He had proved it by His miracles. They did not yet understand what God would accomplish through Christ's death, burial, and resurrection, and they saw Him as only for the nation of Israel.