“And teach customs, which are not lawful for us to receive, neither to observe, being Romans.”
King James Version (KJV)
16:21 And teach customs which it is not lawful for us to receive - The world has received all the rules and doctrines of all the philosophers that ever were. But this is a property of Gospel truth: it has something in it peculiarly intolerable to the world.
Ac 16:21 Teach customs . . . not lawful. According to Howson, Roman law sternly forbade one not a Jew to be circumcised. Paul and Silas did not teach this, but it was a safe charge to make, they being Jews.