Jesus answered, "Most assuredly I tell you, unless one is born of water and spirit, he can't enter into the Kingdom of God!
Now, whereas the operation of the ceremony of baptism itself is retrospective regarding past sins, the second element of the new birth, the reception of the Holy Spirit, is prospective and looks to the perfection of the believer in Christ.  It is this progressive work of the Holy Spirit that leads to a greater and greater degree of sanctification in the heart of the saved.  For more on sanctification see my Commentary on Romans,  Romans 6:22.