Who did Saul persecute when Stephen was killed?
When Stephen was martyred, Saul of Tarsus began a rampage against the believing Jews in Jerusalem and Judea. These were Jews who had trusted in Jesus of Nazareth, still under Judaism's umbrella. He persecuted them thinking he was doing God a service.
Les explains that these were believing Jews at Jerusalem, an Ecclesia called out of Judaism but still under its umbrella, meeting apart yet not separated from the Law or temple worship. Saul's rampage began when Stephen was martyred in chapter 7. Not satisfied with what he accomplished in Jerusalem and Judea, he wanted to go after the believing Jews at Damascus. He did all this in the name of religion, thinking he was serving God by stamping out any believing in Jesus of Nazareth.