In doing this project you encounter weeks like this week without many citations. It always feels a bit of a shame, especially when the set of texts are as good as the ones we get this week. But here's what there is in the Book of Concord for this Sunday's texts.
Verse 8 is cited in the Apology of the Augsburg Confession, Article 12: Repentance (AP 12.122), as one of the texts used in the Confutation of the Augsburg Confession supporting the idea that contrition included acts intended to placate God for sin. Melanchthon, of course, call this a misreading of the text, noting that such acts of contrition are part of church discipline, intended to reincorperate people into the community of faith, not to placate God.
Yup, that's it. Not too much help. But it is a helpful remind to ask ourselves not only, "What then should we do?" but also, "Why are we doing this?"