The teaching is based on the Scripture lessons from Trinity 13. 

• 2 Chronicles 28:8-15
• Psalm 32
• Galatians 3:15-22
• Luke 10:23-37

Here's the quote I referenced from Martin Luther:

Faith is due to God alone; faith receives divine works that God alone can do, and these works of God we can receive alone through faith. Then we should be busy for our neighbors’ sake and direct our works toward them, that these works may serve them. My faith I must bring inwardly and upward to God, but my works I must do outwardly and downward to my neighbor.

Martin Luther, Sermon on the Fourth Sunday after Trinity