The milkmaid and baker as God's "masks"

In a section on the cultural challenges to our understanding of the doctrine of providence in The Christian Faith, Michael Horton observes:

Luther spoke of the milkmaid and the baker as “masks” God hides behind in order to answer our prayer for daily sustenance. In every gift, God is ultimately the giver; yet tenderly he hides his blinding majesty and otherwise terrifying sovereignty behind the creaturely means that are familiar to us. However, those of us in technologically developed cultures rarely encounter the milkmaids and bakers whose goods we purchase at the supermarket…. Our piety—praying for our daily bread—often seems remote from our actual experience, at least in highly developed societies (p. 353).