Luther on Stewardship
Who then can comprehend the lofty dignity of the Christian? By virtue of his royal power he rules over all things, death, life, and sin, and through his priestly glory is omnipotent with God because he does the things which God asks and desires, as it is written, “He will fulfil the desire of those who fear him; he also will hear their cry and save them” [Cf. Phil. 4:13]. To this glory a man attains, certainly not by any works of his, but by faith alone.
From this anyone can clearly see how a Christian is free from all things and over all things so that he needs no works to make him righteous and save him, since faith alone abundantly confers all these things. Should he grow so foolish, however, as to presume to become righteous, free, saved, and a Christian by means of some good work, he would instantly lose faith and all its benefits, a foolishness aptly illustrated in the fable of the dog who runs along a stream with a piece of meat in his mouth and, deceived by the reflection of the meat in the water, opens his mouth to snap at it and so loses both the meat and the reflection.
Luther’s Works, Volume 31, pages 355-356