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!

Isaiah 58:1-12

Is it not to share your bread with the hungry,
and bring the homeless poor into your house;
when you see the naked, to cover them,
and not to hide yourself from your own kin? …
Then you shall call, and the Lord will answer;
you shall cry for help, and he will say, Here I am.
If you remove the yoke from among you,
the pointing of the finger, the speaking of evil…
— Isaiah 58:7, 9

Verses 7 and 9 are cited in Apology of the Augsburg Confession, Article 4: Justification (AP 4.159, quarto) where Melanchthon notes an argument in the Confutation about works with a predictable response that without faith works are nothing.

Psalm 51:1-17

For I know my transgressions,
and my sin is ever before me.
— Psalm 51:3

Verse 3 is cited in a footnote to Formula of Concord, Solid Declaration, Article 1: Original Sin (SD 1.51, n. 42) showing the references for Luther's unpacking of this verse in Luther's Works.

Against you, you alone, have I sinned,
and done what is evil in your sight,
so that you are justified in your sentence
and blameless when you pass judgment.
— Psalm 51:4

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.

Indeed, I was born guilty,
a sinner when my mother conceived me.
— Psalm 51:5

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.

Create in me a clean heart, O God,
and put a new and right spirit within me. …
Restore to me the joy of your salvation,
and sustain in me a willing spirit.
— Psalm 51:10, 12

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.

For you have no delight in sacrifice;
if I were to give a burnt offering, you would not be pleased.
The sacrifice acceptable to God is a broken spirit;
a broken and contrite heart, O God, you will not despise.
— Psalm 51:16-17

Verses 16 thru 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. That means that simply going through the motions and saying the words do not make communion efficacious. The gifts and benefits of communion are granted only through faith.

2 Corinthians 5:20b-6:10

So we are ambassadors for Christ, since God is making his appeal through us; we entreat you on behalf of Christ, be reconciled to God.
— 2 Corinthians 5:20

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.

For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.
— 2 Corinthians 5:21

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.
— Formula of Concord, Solid Declaration,
Article 3: Righteousness, Line 54

Third in Solid Declaration, Article 5: Law and Gospel (SD 5.22), verse 21 is quoted 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.
— Formula of Concord, Solid Declaration,
Article 11: Election, Line 15

As we work together with him, we urge you also not to accept the grace of God in vain.
— 2 Corinthians 6:1

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

[Jesus said,] “Do not store up for yourselves treasures on earth, where moth and rust consume and where thieves break in and steal; but store up for yourselves treasures in heaven, where neither moth nor rust consumes and where thieves do not break in and steal.”
— Matthew 6:19-20

Verses 19 thru 20 are cited in a footnote to 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

TheoThru

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 consumerist culture, and even when it comes to spiritual disciplines?