All the First Readings—First, Alternate First, and Semicontinuous First—and all we get is some Psalm citations. And both bring us back to the Old Testament as a way of figuring out something about the Christian life.
With a freewill offering I will sacrifice to you;
I will give thanks to your name, O Lord, for it is good.
— Psalm 54:6
Verse 6 is quoted in Formula of Concord, Solid Declaration, Article 4: Good Works (SD 4.17) to describe—get this—people of the new covenant! Yes, Christians, it is worth going back to the Old Testament to learn how God wants us to live and worship.
Semi - Psalm 1
... but their delight is in the law of the Lord,
and on his law they meditate day and night.
— Psalm 1:2
Verse 2 comes up twice. First, it is quoted by Luther in the preface to The Large Catechism (LC Preface.10) as encouragement "to occupy one's self with God's Word" as the most helpful way to wrestle "against the devil, the world, the flesh, and all evil thoughts."
Verse 2 is also quoted in Formula of Concord, Solid Declaration, Article 6: Concerning the Third Use of the Law (SD 6.4) as a workaround in the issue of whether or not there is a third use of the Law. It's actually quite elegant:
To explain and settle this dispute definitively we unanimously believe, teach, and confess that, although Christians who believe faithfully have been truly converted to God, and have been justified are indeed freed and liberated from the curse of the law, they should daily practice the law of the Lord... For the law is a mirror that accurately depicts the will of God and what pleases him. It should always be held before the faithful and taught among them continuously and diligently.
— Formula of Concord, Solid Declaration, Article 6: The Third Use of the Law, Line 4
Modernity and Post-Modernity both have an unhealthy fixation on the new. If you, like me, live anywhere in the developed Western world, we have to get over it. But in a week when the new iPhone and iOS 12 was released and the new presidential alert system will be tested, it sure seems like we keep looking for the new rather than learning from the old. These citations from Psalms and how the Lutheran Reformers reflected on the past for their lives is a reminder even though God is doing a new thing, the old Law will not be destroyed but fulfilled.
This shift in focus from the new to reflection on the old can help us turn from ridiculous arguments over who will have power in the new kingdom to how we share our faith with those younger than us through what we do and what we say. Welcoming children, or anyone who the culture otherwise deems worthless, is about repentance. Those who call us into service call us to return to a life centered on God’s love for us shown in Jesus.