Then will I sprinkle clean water upon you, and you shall be clean: from all your filthiness, and from all your idols, will I cleanse you.
Read Chapter 36
George Leo Haydock
Water. R. David and the Chaldean explain this of the remission of sin; and all Christians understand it of baptism in water, remitting all offences, Ephesians v. 26., and Titus iii. 5. (Worthington)
He alludes to the purification of the Jews, which prefigured baptism and penance, in which the blood of Christ is applied to our souls. This of course was only fulfilled in his church.