For Christian holiness, or the holiness common to Christendom, is found where the Holy Spirit gives people faith in Christ and thus sanctifies them, Acts 15 [:9], that is, he renews heart, soul, body, work, and conduct, inscribing the commandments of God not on tables of stone, but in hearts of flesh, II Corinthians 3 [:3]. Or, if I may speak plainly, he imparts true knowledge of God, according to the first table, so that those whom he enlightens with true faith can resist all heresies, overcome all false ideas and errors, and thus remain pure in faith in opposition to the devil. He also bestows strength, and comforts timid, despondent, weak consciences against the accusation and turmoil of sin, so that the souls do not succumb or despair, and also do not become terrified of torment, pain, death, and the wrath and judgment of God, but rather, comforted and strengthened in hope, they cheerfully, boldly, and joyfully overcome the devil. He also imparts true fear and love of God, so that we do not despise God and become irritated and angry with his wondrous judgments, but love, praise, thank, and honor him for all that occurs, good or evil. That is called new holy life in the soul, in accordance with the first table of Moses. It is also called tres virtutes theologicas, “the three principal virtues of Christians,” namely, faith, hope, and love; and the Holy Spirit, who imparts, does, and effects this (gained for us by Christ) is therefore called “sanctifier” or “life-giver.” For the old Adam is dead and cannot do it, and in addition has to learn from the law that he is unable to do it and that he is dead; he would not know this of himself. (Luther’s Works, v.41, p.145-146)
Picture: John the Baptist brings a baptism of repentance for the forgiveness of sins.