There are many citations for these texts, especially Psalm 51 and 2 Corinthians. Since these texts are consistent across the lectionary cycles, don't try and do it all at once!
Verses 7 and 9 are cited in Apology of the Augsburg Confession, Article 4: Justification (AP 4.159, Quatro) where Melanchthon notes an argument in the Confutation about works with a predictable response that without faith works are nothing.
Verse 3 is cited in Formula of Concord, Solid Declaration, Article 1: Original Sin (SD 1.51n42) showing the references for Luther's unpacking of this verse in Luther's Works.
Verse 4 is cited in Apology of the Augsburg Confession, Article 12: Repentance (AP 12.108) to show that confession, when made to God, is contrition, so they are not separate steps.
Verse 5 is cited in Smalcald Articles, Part 3, Section 1: Concerning Sin (SA 3.1.3) as Luther argues that the idea of inherited sin cannot be understood by reason. Only faith based in scriptural witness can see the truth of inherited sin.
Verses 10 and 12 are cited in Formula of Concord, Solid Declaration, Article 2: Free Will (SD 2.26) to show that the work of the Holy Spirit in conversion "takes away our hard and stony hearts and replaces them with new, soft hearts of flesh, that we may walk in his commands" (SD 2.26).
Verse 12 is also cited in Formula of Concord, Solid Declaration, Article 2: Free Will (SD 2.60) again showing that conversion is the creation of the new heart.
Verse 16-17 are cited in Apology of the Augsburg Confession, Article 24: The Mass (AP 24.29) as condemnation of an ex opere operato understanding of the mass.
2 Corinthians 5:20b-6:10
Verse 20 is cited twice. First in Apology of the Augsburg Confession, Article 24: The Mass (AP 24.80) to show that the work of the clergy is service (literally liturgy, a public service), not sacrifice. Then in Formula of Concord, Solid Declaration, Article 11: Election (SD 11.27) to show God using means--Paul in this case--to call others through the the word and forgiveness of sins.
Verse 21 is cited several times in Formula of Concord. First in Epitome, Article 3: Righteousness (Ep 3.1) noting that Jesus, who alone is our righteousness, is both fully divine and fully human. Then in Solid Declaration, Article 3: Righteousness (SD 3.54) as an editorial insert based on the Epitome citation, expanding the argument: "this indwelling of God is not the righteousness of faith, which St. Paul treats and calls iustitia Dei (that is, the righteousness of God), for the sake of which we are pronounced righteous before God. Rather, this indwelling is a result of the righteousness of faith which precedes it, and this righteousness [of faith] is nothing else than the forgiveness of sins and the acceptance of poor sinners by grace, only because of Christ's obedience and merit" (SD 3.54). Third in Solid Declaration, Article 5: Law and Gospel (SD 5.22) as a direct quote of the verse in declaration of what the gospel, in the strict sense, is and the difference between the knowledge of God as learned in the law and the knowledge of God as learned in the gospel. Finally, this verse is cited in Solid Declaration, Article 11: Election (SD 11.15) as an editorial insert noting the first of God's preordinations in election: "That the human race has been truly redeemed and reconciled with God through Christ, who has merited with his innocent obedience, suffering, and death both the righteousness that avails before God and eternal life" (SD 11.15).
The fist verse of chapter 6 is cited in Formula of Concord, Solid Declaration, Article 2: Free Will (SD 2.66) noting that any cooperation between the reborn Christian and the Holy Spirit comes from the Holy Spirit and can never be equal. If the Holy Spirit departs, then no good works can be done, since good works are done because of Jesus' faith, which is given to us by the Holy Spirit.
Matthew 6:1-6, 16-21
Verses 19-20 are cited in Large Catechism, The First Part: The Ten Commandments, The Seventh Commandment (LC 1.242 n. 106) as a citation for Luther's harsh words about stealing and the market place. It may be worth reading this whole paragraph (LC 1.240-242), if not this whole section, if you want to go this direction
From whence comes our righteousness, especially as we dedicate a season of the church for some kind of particular discipline? There is always a temptation of picking up a discipline that we might misinterpret what is happening.
- Why do we do the imposition of ashes? - OR - Why don't we do the imposition of ashes?
- Do we think that we can cooperate with the Holy Spirit as an equal?
- Where do we find our righteousness?
- How widely to we break the commandment against stealing, especially with our consumeristic culture, and even when it comes to spiritual disciplines?