Obviously, he is not commanding us to do self-mutilation. This would be morally wrong, because Christianity teaches respect for the body. We are stewards for all that God has given us. We must root out all that entices us away from God and from heaven. This implies not mortification, but modification of what we want out of life.
Instant pleasures bring long-term suffering.
He tells us to dismember ourselves rather than allow sin to cast us into hell. Obviously, he is not commanding us to do self-mutilation. This would be morally wrong, because Christianity teaches respect for the body. We are stewards for all that God has given us. We must root out all that entices us away from God and from heaven.