152 There is a familiar figure of speech, called synecdoche, by which we sometimes combine cause and effect in the same phrase. Christ says in Luke 7:47, “Her sins, which are many, are forgiven, because she loved much.” But he interprets his own words when he adds: “Your faith has saved you” (v. 50). Now Christ did not want to say that by her works of love the woman had merited the forgiveness of sins.
153 Therefore he clearly says, “Your faith has saved you.” But faith is that which grasps God’s free mercy because of God’s Word. If anybody denies that this is faith, he utterly misunderstands the nature of faith.
154 And the account here shows what he calls “love.” The woman came, believing that she should seek the forgiveness of sins from Christ. This is the highest way of worshiping Christ. Nothing greater could she ascribe to him. By looking for the forgiveness of sins from him, she truly acknowledged him as the Messiah. Truly to believe means to think of Christ in this way, and in this way to worship and take hold of him. Moreover, Christ used the word “love” not toward the woman but against the Pharisee, because Christ contrasted the whole act of reverence of the Pharisee with that of the woman. He chides the Pharisee for not acknowledging him as the Messiah, though he did show him the outward courtesies due a guest and a great and holy man. He points to the woman and praises her reverence, her anointing and crying, all of which were a sign and confession of faith that she was looking for the forgiveness of sins from Christ. It was not without reason that this truly powerful example moved Christ to chide the Pharisee, this wise and honest but unbelieving man. He charges him with irreverence and reproves him with the example of the woman. What a disgrace that an uneducated woman should believe God, while a doctor of the law does not believe or accept the Messiah or seek from him the forgiveness of sins and salvation!
155 In this way, therefore, he praises her entire act of worship, as the Scriptures often do when they include many things in one phrase. Later we shall take up similar passages, like Luke 11:41, “Give alms; and behold, everything is clean.” He demands not only alms, but also the righteousness of faith. In the same way he says here, “Her sins, which are many, are forgiven, because she loved much,” that is, because she truly worshiped me with faith and with the acts and signs of faith. He includes the whole act of worship; but meanwhile he teaches that it is faith that properly accepts the forgiveness of sins, though love, confession, and other good fruits ought to follow. He does not mean that these fruits are the price of propitiation which earns the forgiveness of sins that reconciles us to God.
-Apology, IV (V). Love and the Fulfilling of the Law, 152-155 (HT: Pastor Gillespie at Outer Rim Territories 8/30/2013)