Cleansing of Spirit

Heb 9:10-14
10 since they {relate} only to food and drink and various washings, regulations for the body imposed until a time of reformation.11 But when Christ appeared {as} a high priest of the good things to come, {He entered} through the greater and more perfect tabernacle, not made with hands, that is to say, not of this creation;12 and not through the blood of goats and calves, but through His own blood, He entered the holy place once for all, having obtained eternal redemption.13 For if the blood of goats and bulls and the ashes of a heifer sprinkling those who have been defiled, sanctify for the cleansing of the flesh,14 how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?(NAS)

In this passage, the "they" is referring to the old covenant of animal sacrifice in the tabernacle and the annual visits to the Holy of Holies. Christ's coming changed everything. With the old covenant, sins were forgiven, but the guilt remained. Christ sacrifice not only removes the sin, but the guilt along with it. We no longer have anything to fear, Jesus has taken care of it. The old system cleaned the flesh, the new cleanses the spirit.