And I said, Lord - This shows that it was the Lord Jesus whom Paul saw in a trance in the temple. The term “Lord” is usually applied to him in the Acts . See the notes on Acts 1:24.
They know - Christians know; and they will therefore be not likely to receive to their fellowship their former enemy and persecutor.
Beat in every synagogue - Beating, or scourging, was often done in the synagogue. See the notes on Matthew 10:17. Compare Acts 26:11. It was customary for those who were converted to Christianity still to meet with the Jews in their synagogues, and to join with them in their worship.