Luther discovered as ‘justification by God’s word’ instead of ‘justification by faith’, because it is God’s word that justifies here, not our faith. Faith, thought Luther, is not some inner resource we must summon up; if it were, it would by his definition be sin! For him, the question ‘Have I got enough faith?’ completely misunderstands what faith is, by looking to and so relying on itself, rather than Christ. Faith is a passive thing, simply accepting, receiving, believing Christ—taking God seriously in what he promises in the gospel.
It is the object of faith that saves, namely Christ, and not the strength. Like a parachute, there are those who put it on and love it, understand it, and don't doubt its ability to save. But there are also those who put it on and are fearful and doubt that it will work. At the end of the day, when the plane crashes, both will be saved based on the parachute's effectiveness and not based on their feelings.
