"The right way to become a Christian is to be justified by faith in Christ, and not by the observance of the law. Here we must stand, and not upon the wicked interpretation of those who say that faith justifies when love and good works are combined with it. That interpretation obscures this and similar sentences in Paul in which he clearly attributes justification solely to faith in Christ. When people hear that they should believe in Christ, yet faith only justifies if it is formed and accompanied by works of love, eventually they fall from faith and think along these lines: 'If faith without love does not justify, then faith is empty and pointless, and only love in action justifies, for faith is nothing without love....'
"They say that faith in Christ does not make us free from sin, but only faith combined with love. this is to say that Christ leaves us in our sins and in the wrath of God and makes us guilty of eternal death, whereas if you keep the law, faith justifies you because it has works, without which faith is no help. Therefore, works justify, and not faith, they claim. What pernicious and cursed teaching is this!"
Martin Luther, Galatians, pp. 90, 93-94.