Martin Luther said many things, but as with many famous people, he did not say a handful of things people attribute to him, such as:

The maid who sweeps her kitchen is doing the will of God just as much as the monk who prays—not because she may sing a Christian hymn as she sweeps but because God loves clean floors.

The Christian shoemaker does his Christian duty not by putting little crosses on the shoes, but by making good shoes, because God is interested in good craftsmanship.

Justin Taylor explains:

Luther didn’t say this. As with the quote from the first example, [Frederick] Gaiser argues that it doesn’t sit very well with Luther’s actual views on vocation. The idea that God is pleased with our work because he likes quality work “would be the American work-ethic version of vocation, theologically endorsing work as an end in itself. In the hands and mouth of a modern boss, good craftsmanship and clean floors (or a clean desk or a signed contract) to the glory of God could be a potent and tyrannical tool to promote the bottom line. . . . [W]hat marks Luther’s doctrine of vocation is the insistence that the work is done in service of the neighbor and of the world. God likes shoes (and good ones!) not for their own sake, but because the neighbor needs shoes. . . .”