I have said that in this manner one must care for the body and protect a good reputation, wife, children, and the whole household, and that, so far as possible, one must do everything that pertains to the preservation of these. For if everyone were to neglect giving attention to his own affairs and to his office, whether publicly or privately, I, too, would neglect the office entrusted to me and would be able to say: “Why do we preach, teach, and baptize?” And yet God did not create us and put us into this world that we should abandon ourselves to ease and pleasures and thus east every care upon God (1 Peter 5:7), as if there were nothing whatever for us to do. But when a person has done his duty in his own position, then indeed the success and outcome of all activities must be entrusted to God. Thus a farmer does not commit the care of his field to God in such a way that he himself does none of the things that pertain to agriculture, does not plow, and does not cultivate the land; but after doing all these things, then indeed he asks God for increase and favorable weather. If we are heard by God, let us be thankful. If not, let us bear it patiently and render due obedience, in order that we may learn what the perfect and pleasing will of God is in us (Rom. 12:2).
Luther’s works, vol. 7: Lectures on Genesis: Chapters 38-44 p 115