This week we bring together the goodness of the law and the certainty of faith.
... but their delight is in the law of the Lord,
and on his law they meditate day and night.
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
1 John 5:9-13
Those who believe in the Son of God have the testimony in their hearts. Those who do not believe in God have made him a liar by not believing in the testimony that God has given concerning his Son.
-- 1 John 5:10
Verse 10 is cited twice in Apology of the Augsburg Confession, Article 12: Repentance. First it is quoted (AP 12.62) to show that absolution requires faith. Melanchthon's argument in this section is that a general faith in the existence of some god is not the same thing at the faith that save. The saving faith is faith that God forgives us our sins because of Jesus, therefore receiving the forgiveness of sin requires this saving faith because it is this saving faith. If you do not believe that your sins are forgiven but do believe in God, then you have made God a lair...
Verse 10 is cited a bit later (AP 12.88) to get at this point from a different direction. There is a question asked by Chrysostom, and early leader of the church, that is picked up by those standing against Melanchthon and the other reformers: How can we be certain that our sins are forgiven? Melanchthon's answer is faith.
This [question] cannot be answered, nor can our consciences find rest, unless they know it is God's command and the gospel itself that they should be certain that their sins are forgiven freely on account of Christ and not doubt that they are personally forgiven.
-- Apology of the Augsburg Confession, Article 12: Repentance, Line 88
This is our faith: we believe that God forgives us our sin for Jesus' sake. To doubt this is to doubt God.
Whoever has the Son has life; whoever does not have the Son of God does not have life.
-- 1 John 5:12
The first phrase of verse 12 is quoted in Apology of the Augsburg Confession, Article 4: Justification (AP 4.334ish) as a quick summary of the Reformer's approach to faith. The necessary faith that saves is belief "that God remits sins, justifies, and gives eternal life on account of Christ and not on account of the law." Whoever believes this has the Son, and so has life. As the Small Catechism remind us, "where there is forgiveness of sin, there is also life and salvation" (SC 5.6).
Sanctify them in the truth; your word is truth.
-- John 17:17
Verse 17 is quoted (and elided with verse 20) in Formula of Concord, Solid Declaration, Article 2: Free Will (SD 2.51) in the middle of several scriptural quotes showing how God provides for the proclamation of the gospel that leads to sanctification.
These citations raise up a solid point about faith: there are different kinds of faith.
I hope that's not a surprise, but I'm not sure we talk about it very much. How you live your life may be very different if you believe that there is a god but don't believe that god loves you and if you believe that God our of love became human, died, and rose again so that your sins might not keep you out of this loving God's presence. The first faith probably leads to either a life of fear or antipathy toward that uncaring god. The second faith leads to salvation, freedom from fear of judgment, and hope.
This also makes plain the reality of spiritual warfare, even if just within each person. We either believe the proclamation and testimony of the loving God, or we call that God a liar. Such a clear contrast, but complicated by the reality that each of us does both of these. Sometimes even at the same time. The old person in each of us calls God a liar and hates the law, while the new person in us believes God's forgiveness and love and finds the law helpful for guidance and practice.