For the fulfillment of His purpose God needs more than priests, bishops, pastors, and missionaries. He needs mechanics and chemists, gardeners and street sweepers, dressmakers and cooks, tradesmen, physicians, philosophers, judges, and shorthand typists. “My brethren,” writes St. James, “show no partiality as you hold the faith of our Lord Jesus Christ, the Lord of glory.” (James 2:1) Having a vocation means approaching everything one does in a spirit of vocation, looking upon it as an adventure shared with God. “In all toil there is profit” (Proverbs 14:23) or, as Calvin put it, in his pungent style, “there can be no work, however vile or sorted, that does not glisten before God, and is not right precious, provided that in it we serve our vocation...Every man in his place ought to deem that his estate is, as it were, a station assigned him by God.
I do not serve God only in the brief moments during which I am taking part in a religious service, or reading the Bible, or saying my prayers, or talking about Him in some book I am writing, or discussing the meaning of life with a patient or a friend. I serve him quite as much when I am giving a patient an injection, or lancing an abscess, or writing a prescription, or giving a piece of good advice. Or again, I serve Him quite as much when I am reading the newspaper, traveling, laughing at a joke, or soldering a joint in an electric wire. I serve him by taking an interest in everything, because He is interested in everything, because He has created everything and has put me in His creation so that I may participate in it fully.” (Paul Tournier, The Adventure of Living, page 209-10)
See also -- Tournier on Work as a Divine Gift (& Calling)