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,
(5) It was the water of the flood which washed away the filth of that evil generation; and it is the water of Christian baptism that, in a figure, washes away the sins of Christians (Acts 22:16).  There is a variation in the figure here, which Peter pointed out; namely, that, whereas it was actual filth that was washed away by the flood, it is moral and spiritual filth which are washed away in baptism.  The former affected the flesh and not the conscience; the latter affected the conscience but not the flesh.