It's hard to let go of something familiar, even if it's not the thing that's best. That's what was happening with Jewish evangelists who contradicted the message of the apostles by telling them that they needed to follow old Jewish rituals to be believers. Their error is easy for us to see, but perhaps not so much for those who were trying to figure out how a religion started by a Jewish rabbi fit without being totally Jewish. Being a member of the early Church wasn't easy!