Martin Luther on Work

I'm reading a book on the relationship between Work and God. Our work matters to God, and God matters to our work. I've still got a long way to go, but I came across this quote from Martin Luther, where it says,

Luther observed that God's blessings at times come to us through our labors and at times without our labors, but never because of our labors; for God always gives them because of His undeserved mercy...He uses our labor as a sort of mask, under the cover of which he blesses us and grants us what is His, so that there is room for faith.

More to come on the issue of work from a Gospel-centered perspective...