I consider Steven Garber to be a friend and mentor- the privilege of the last five years have in large part been due to my time spent with him in my doctor of ministry program. I cannot recommend highly enough to you his book Visions of Vocation. Here I quote an excerpt:
But when I was twenty, . . . in my own late-adolescent longings I thought Marx was close to the truth. He had a passionate commitment to a just world; at least it seemed so to me in my young idealism. He had a comprehensive critique of the world, and of our place in it, and I desperately wanted that too. But as tempted as I was by him, eventually I was drawn even more into another vision of the way the world should be–that of the kingdom of God. When push came to intellectual shove, the Christian vision for the way life ought to be answered my questions and addressed my hopes more fully than did Marx's–and it still does, more than ever.
Visions of Vocation, p. 215