This post is part of an ongoing series on Forgiveness in the Gospel of Matthew.
While increased attention has been paid to Matthew’s overarching theology of forgiveness in recent years, no study has comprehensively treated this theme. Here, we begin the process of tracing Matthew’s theology of forgiveness, considering literary-theological passages, parables, and narrative insights into the importance of forgiveness for the Christian community.
Matthew’s theology of forgiveness begins at the beginning of his gospel, when at the annunciation Joseph is told that Jesus will “save his people from their sins.” Thus from the start readers of the First Gospel are alerted to the fact that Jesus’ salvific import coordinates with the removal of sins—an act of merciful forgiveness. In the Lord’s Prayer, Jesus petitions that God forgive us as we forgive others (6:12), continuing after the prayer with the explanation that, “if you forgive others their trespasses, your heavenly Father will also forgive you; but if you do not forgive others, neither will your Father forgive your trespasses” (6:14-15). This postscript is found neither in Luke 11:1-4 nor in Mark 11:25. The theme of “forgive in order that you may be forgiven” that occurs in the Parable of the Unmerciful Servant stands in coordination with this petition from the Lord’s Prayer. Even more important for Matthew’s theology of forgiveness, however, is his affirmation of the Jewish conviction that Yahweh is the one who effects the forgiveness sin.
Matthew continues the development of this theme in 9:1-8, where Jesus confirms his power to forgive sins—just like Yahweh—in the healing of the paralyzed man. The next encounter with forgiveness occurs in Jesus’ discussion of spiritual powers in Matthew 12:31-32, where he speaks of the unforgiveable sin of speaking against the Spirit (εἴπῃ κατὰ τοῦ πνεύματος, 12:32), where to “speak against” conveys not only actual speech, but also general transgression of the will of the Spirit. Less frequently noted is this passage’s differentiation between the Son and the Spirit. Whereas sins against the Spirit are unforgiveable, general sins and even speaking against the Son of Man will be forgiven (ἀφεθήσεται). Scholars have spilled no little ink over attempting to determine what this unforgiveable sin might be. In light of Matthew 18:21-35 and Matthew’s other insights into instances of unforgiveness, it seems plausible that not living out the Spirit’s forgiveness could in fact constitute “speaking against” the Spirit. That is, for Matthew, the unforgiveable sin for Christians is not extending the forgiveness of God to others, thereby transgressing the Spirit of God.
The final literary-theological insight on forgiveness involves the institution of the Lord’s Supper in Matthew 26:26-30, where Jesus announces that it his blood which, when poured out, provides for the forgiveness of sins (εἰς ἄφεσιν ἁμαρτιῶν). While Mark 11:22-25, Luke 22:15-20, and Paul (1 Corinthians 11:23-25) all record this all-important scene—including the institution of the supper and the inauguration of the new covenant—no other account of the Lord’s Supper indicates that Jesus’ blood is for the forgiveness of sins. Unique to Matthew’s Gospel, therefore, is the continuation of the Jewish belief that without the blood there is no forgiveness of sins and that is it Jesus’ blood in particular which forgives human sinfulness. These literary-theological insights reveal that, for Matthew, Jesus came into the world in order to save people from their sins, that God (alone) possesses the power to forgive, that Jesus too has been given the power to grant forgiveness, that sins against the Spirit are unforgiveable, that sins against the Son are forgivable, and that Jesus’ blood brings forgiveness of sins.
 Bronn, 208-209, notes connections between 5.21–24, 6.15, and 18.15-35, but no other passages. Even Mbabazi’s careful consideration of Matthew’ concept of forgiveness overlooks many of the contributions to Matthew’s overarching theology. See Isaac Kahwa Mbabazi, The Significance of Interpersonal Forgiveness in Matthew’s Gospel (PhD Diss., Manchester: University of Manchester, 2011), esp. 57-67.
 Novum Testamentum Graece, Nestle-Aland 27 (ed. Kurt Aland, Westphalia: Deutsche Bibelgesellschaft, 2011), 2. αὐτὸς γὰρ σώσει τὸν λαὸν αὐτοῦ ἀπὸ τῶν ἁμαρτιῶν αὐτῶν.
 In the petition, Jesus uses the imperative (ἄφες)—conveying request—and in the explanation he employs the subjunctive (ἀφῆτε)—indicating the conditional nature of the forgiveness.
 Bronn, 208-209. Bronn concludes that, “Not only is it clear that Matthew has a special interest in forgiveness but, looking back, we see that he speaks of forgiveness almost exclusively in terms of brotherhood.”
 John S. Kselman, “Forgiveness: Old Testament,” 831-833 in The Anchor Bible Dictionary: Volume 2 (D-G) (New York/London: Doubleday, 1992), 831. Cx. Ex. 34.6-7, Num. 14.8, 30.6-13. Daniel Johansson, “’Who can forgive sins but God alone?’: Human and Angelic Agents, and Divine Forgiveness in Early Judaism,” JSNT 33.4 (2011): 351-374.
 The phrase “εἴπῃ κατὰ” is not extant in any literature prior to Matthew’s Gospel. On use of term, see Galen, In Hippocratis 17b.96.7 and Hermogenes, Rhetoric 1.50.
 See Luz, 206-210 on the history of interpretations of this passage, ranging from Origen to modern scholars.
 Ex. 30.10, Lev. 2.9. 3.5, Ez. 45.18-20. See also Heb. 9.22. Anna Suk Yee Lee, “Forgiveness and Reconciliation in Old Testament Sacrifice,” McMaster Journal Of Theology & Ministry 13 (2011): 24-44, esp. 25.