While baptism is a “once and for all” event that should not be repeated in the Christian’s life, the effects of baptism continue throughout the life of the believer.
Take away the communal aspect, take away the communal gathering around Christ’s body and blood, and the Christian will begin to suffer a malnutrition of faith.
Despite what the Pharisees believed and advertised, Jesus was not intent upon deconstructing the fundamental tenets of the Old Testament law. Actually, he proceeds to do just the opposite.