Everyone worships something. Self, stuff, or supernatural. What's the motivation for someone to arrive at the doorstep of their "god"?
I believe deeply in the existence of Someone bigger than me. While I am intimately familiar with the "calling of God," and subsequently believe that the ones brought into relationship with Him are chosen by Him, my culture loves to argue the point that it's merely a pathetic attempt to make sense of a senseless life; that I only depend on those beliefs because I am too weak to make it on my own.
But you cannot escape the fact that human beings are hardwired to make sense out of the senseless. Therefore we pursue the things that lead us to our goal. Society's gods can be found in self, stuff, or supernatural beliefs. The problem arises in the choosing of those three. You cannot sensibly choose all three. If I am wrong, and there is no God who calls his followers, then what motivates people to make their choice?