The Work of the Unqualified
At multiple junctures in my life I've been reminded of just how much God enjoys using the "unqualified" to do His great work. As Paul recognized from his own life, "in my weakness You are strong." It's an important thing for us to remember, because God tends to push and put us in situations where we are acutely aware of our inadequacy...which is the point. How will we respond when pushed into a position of dependency and self-insufficiency?
Here's a fairly good commentary on that very subject by means of a quick survey of Biblical characters who wrestled with similar anxieties:
http://www.sermoncloud.com/austin-bible-fellowship/unqualified
(be sure to click the "read more" hyperlink under the first 2 paragraphs of sample text)