In the course of discussing the call of God, in particular the journey of Moses, a student once told me, "God doesn't choose the prepared. He prepares the chosen."
I'm not sure where she heard that line (it was not original to her), but her comments have always struck me as a wonderfully simple way to understand our earthly labors in view of the Kingdom of God.
God calls us despite our shortcomings; more than that, it seems that God calls us (sometimes, at least) because of our shortcomings. Too often we think we have to be perfect; we think we have to have it all figured out, whether in our careers, in our families, or in our general planning for life. How much energy and peace of mind do we burn worrying that we unworthy of where we are, or what we are called to do?
God wants a project; God wants each of us to be a scene of miracle. In our own hearts, he wants to part the sea.