What is our work in field and garden, in town and houses, in battling and in ruling, to God, but the work of children through which He bestows His gifts on the land, in the house, and everywhere? Our works are God's masks, behind which He remains hidden, although He does all things. If Gideon had not obeyed and gone to battle with Midian, the Midianites would never have been conquered, although God could, of course, have conquered them without Gideon. He could also give you corn and fruit without your plowing and planting, but that is not His will; neither is it His will that your plowing and planting should produce corn and fruit; but you must plow and plant and say a blessing on your work and pray: Now help, O God; give us now corn and fruit, dear Lord; for our plowing and planting will not yield us anything. It is Thy gift.
God is the giver of all good gifts; but you must fall to, and take the bull by the horns, which means you must work to give God and occasion and a mask.
~ Martin Luther, from Exposition of Psalm 147, qtd. in Day by Day We Magnify Thee