Jesus was telling Saul that he was in rebellion against Him. Jesus instructed Ananias to go and meet up with Saul. He was nervous/scared to do this because he had heard unpleasant things about him. The religious leaders went about trying to kill Saul in the same way that he went about trying to kill the Christians earlier. In Acts 22, Paul is giving his own testimony. Repentance is necessary for salvation. Religion is man trying to reach up to God. Christianity is God reaching down to have a fellowship with us.