Recently Gene Edward Veith published an article on vocation in World Magazine.  The whole thing is worth reading but I've posted a few quotes below.

God thus looms behind everyone who provides us with the goods or services that we need. In one of Luther's many memorable lines, God milks the cows through the hands of the milkmaid. This means that all work and all workers deserve honor. Whereas the world might look down on milkmaids and garbage collectors, they actually bear the sacred presence of God, who works in and through them.

God created us to be dependent on others—meat processors, manufacturers, journalists, lawyers, bankers, teachers, parents—and, through them, we are ultimately dependent upon God Himself.

Just as God is working through the vocation of others to bless us, He is working through us to bless others. In our vocations, we work side-by-side with God, as it were, taking part in His ceaseless creative activity and laboring with Him as He providentially cares for His creation.

and...

In all our religious and ethical life," says Einar Billing in his classic work on vocation, Our Calling, "we are given to an incredible overestimation of the extraordinary at the expense of the ordinary." We look for miracles, spectacular events , and mountain top experiences. Meanwhile, the spiritual significance of everyday life gets overlooked. Vocation, though, transfigures our ordinary, mundane existence, charging it with spiritual significance and with the very presence of God.

Luther said that changing a baby's diaper is a holy work. A child doing his chores is outperforming the Carthusian monks in works of holiness. By extension, we can see the office desk, the factory machinery, the computer screen—likewise the voting booth, the marriage bed, the dining room table—as altars upon which we exercise our royal priesthood.

finally...

Vocation changes the quality of what we do. An artist with a sense of vocation will create not just to express himself or to advance his career but to love and serve—not corrupt or ridicule—his audience. A businessman who sees his customers as the objects of his Christian love will serve them with his very best work.

From the outside, the economy has to do with the division of labor, individuals pursuing their own self-interests, laws of supply and demand, and other impersonal forces. And so it is, as part of God's created order. From the inside, however, the economy can become transfigured into a vast network of mutual dependence and mutual service, and economic activity can become an expression of love.

Christians can celebrate on Labor Day the joining of our work with God's work.

(HT: Justin Buzzard)