In Romans 7, St. Paul says, "The law is spiritual." What does that mean? If the law were physical, then it could be satisfied by works, but since it is spiritual, no one can satisfy it unless everything he does springs from the depths of the heart. But no one can give such a heart except the Spirit of God, who makes the person be like the law, so that he actually conceives a heartfelt longing for the law and henceforward does everything, not through fear or coercion, but from a free heart.
Martin LutherFaith is a living, bold trust in God's grace, so certain of God's favour that it would risk death a thousand times trusting in it. Such confidence and knowledge of God's grace makes you happy, joyful and bold in your relationship to God and all creatures. The Holy Spirit makes this happen through faith. Because of it, you freely, willingly and joyfully do good to everyone, serve everyone, suffer all kinds of things, love and praise the God who has shown you such grace.
Martin LutherIf you preach the gospel in all aspects with the exception of the issues which deal specifically with your time, you are not preaching the gospel at all.
Martin LutherThe article of justification is fragile. Not in itself, of course, but in us. I know how quickly a person can forfeit the joy of the Gospel.
Martin Luther