This is virtually a definition of baptism. Baptism is an outward expression of a spiritual, inward appeal to God for cleansing. Baptism may cleanse the body because it was by immersion. But that is not why he says it saves. It is an appeal of faith.
Baptism is such a calling.
It is an appeal to the Lord. We have been buried with Christ and we have risen with him. We have passed from death to life. Judgment is past. The suffering we are experiencing cannot be the condemnation of God.