Where did Peter and John go in Acts 3, and why?
Peter and John went up together into the temple at the hour of prayer (Acts 3:1). This was because Israel was still under the law, the temple was operating, and designated hours of prayer were part of Jewish practice. They were not going out to the church.
Les explains that in Acts 3, Peter and John are going to the temple, not out to the church. He emphasizes that all during Christ's earthly ministry Israel was under the law, and the temple was operating. Even after Christ's death, burial, resurrection, and ascension, the temple continued. Les points out that Christianity does not have designated hours of prayer like the Muslim world or others; the hour of prayer belonged to Israel's temple practice. This fits the whole kingdom promise to the nation of Israel still in view.
Now Peter and John went up together into the temple at the hour of prayer, being the ninth hour.