In this sermon Jesus' Authority Upon The Church, It might sound severe to cut off a member of the church from the church. However, it's required if the offending member is genuinely offending God's little children and there's no remorse in doing it. The words concerning cutting off the offensive hand or foot are used as a principle in the Bible. Principles are true cases that apply to situations given the specific circumstances that cause the situation to fit the rule. In this case, Jesus is applying the principle to the issue of handling those church members who offend the others.