Why was Paul allowed to put Jewish believers to death?
Paul was permitted because Rome granted Judaism, an ancient religion it respected, authority to execute its own people. Acting under authority from the chief priests, he imprisoned and voted to put Jewish believers to death as heretics, and Rome did not intervene, since such permission did not extend to Gentiles.
Les explains that Rome tolerated Judaism because it was an ancient religion. The Romans allowed the Jews to maintain their temple worship and even guaranteed safe delivery for offerings sent back to Jerusalem. They gave Jewish authorities permission to put their own people to death. So Paul, having received authority from the chief priests, could shut up saints in prison and vote to put them to death as heretics, considered the off-scouring of Judaism. Rome would never have allowed that to happen to a Gentile. Rome respected ancient religions, but when Christianity appeared as something new, Rome tried every way to stamp it out, which is why Christians came under massive persecution while the Jews did not.