Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration and renewing of the Holy Ghost; Which he shed on us abundantly through Jesus Christ our Saviour; That being justified by his grace we should be made heirs according to the hope of eternal life!—Titus, 3:5-7.
It is not by works of righteousness, but according to his mercy. It is by the washing of regeneration, and renewing of the Holy Ghost. It is a cleansing "with the washing of water by the word" (Ephesians, 5: 26).
The word does not act upon our supposed material body, but upon our mentality. As water is applied to an earthen vessel, so the word is applied to our mental being.