Did the Jerusalem believers separate from the Law and temple worship?
No, the Jerusalem believers did not separate from the Law or temple worship. They were a called-out assembly of believing Jews who met apart but remained under the total umbrella of Judaism, still participating in temple worship and Law observance.
Les explains that these Jerusalem believers were an Ecclesia, a called-out assembly. They were called out of Judaism and met apart, yet they remained under the total umbrella of Judaism. They had not separated themselves from the Law, from temple worship, and similar practices, but were assembling as believing Jews. This context sets the stage for Saul of Tarsus, who later began his rampage against these believing Jews, thinking he was doing God a service by stamping out faith in Jesus of Nazareth.