Who is the most vicious and most ready to kill, according to this lesson?
A religious person is identified as the most vicious and most ready to kill. In this context, that means the Judaizers, who were wrapped up in Old Testament religion yet willing to kill anyone who opposed them. Paul himself acted this way, imprisoning saints and voting against them when they were put to death.
Les explains that Paul rehearses his conversion three times—Acts 9, Acts 22, and Acts 26—and in Acts 26:9 he admits he thought he ought to do many things contrary to Jesus of Nazareth. Paul shut up saints in prison with authority from the chief priests, and when they were put to death he gave his voice or vote against them. Les emphasizes that these Judaizers were so wrapped up in their Old Testament religion that they were ready to kill anybody who opposed them. He says there is no one so vicious and no one so ready to kill as a religious person, distinguishing that from Christianity and pointing to wars raging in the name of religion.