Martin Luther is arguably best known for his argument that the “just shall live by faith.” His creed sola fide captures this biblical principle and he raises it quite about in Concerning Christian Liberty.
For Luther, faith is an inward action: it is an action that is done within the person. Of course, they will outwardly confirm the inward reality through public confession (baptism, their life, and participation in Eucharist) and through a life that bears the fruit of the Spirit living within them (see Galatians 5:22-23).
Paul wrote in Romans 10:9, “For with the heart, one believes and is justified, and the mouth one confesses and is saved.” Out of the new life rooted in the heart of the Christian, they then confirm the inward reality to others. While they ought to live differently, no outer works can ever replace what happened inwardly.
Let me put it another way. Psalm 1 describes the righteous person as a tree planted by streams of living water. This tree, out of a place of health and growth from the living water, will then produce fruit and shade for others. Out of the tree’s health it then demonstrates that health through outer means.
Luther argued that the only work we need as a Christian is to lay aside our works and trust in the work of God in Jesus. As John 6:27, 29 asserts
“Do not work for the food that perishes, but for the food that endures to eternal life, which the Son of Man will give to you. For on him God the Father has set his seal.’…Jesus answered them, ‘This is the work of God, that you believe in him whom he has sent.’”
If you don’t catch anything though, catch this: everything is dependent on faith. If you have faith, then you have everything. If you don’t have it, then you have nothing. Putting faith in Christ will lead to life and to all the blessings God promises his people. They will find rest in seas of turmoil and peace in the darkest valleys, for one day Christ will put this world to rights and will wipe away every tear. As Tullian Tchividjian put it recently in a book: Jesus + Nothing = Everything.