This is a symbol of baptism, which now saves you-- not the putting away of the filth of the flesh, but the answer of a good conscience toward God, through the resurrection of Jesus Christ,

 It may be that we will never agree in our theories of what exactly happened on the Cross, for, indeed, as Charles Wesley said in that same hymn: "'Tis mystery all!" But on one thing we can agree--through what happened there we may enter into a new relationship with God. 