Peter, who first introduces believers' baptism in Acts 2, clarifies its meaning in his epistle when he compares baptism, not to a bath, but to the Noaic flood. As in Noah’s flood, where the waters both judged the ungodly and saved the obedient, baptism represents our voluntary submission to the judgment of sin on the cross and the subsequent resurrection to spiritual life. This act of baptism is a vow of commitment to the saving relationship with Jesus that constitutes salvation.