“Our hearts are like that. We think we've learned about grace, set our idols aside, and reached a place where we're serving God not for what we're going to get from him, but for who he is. There's a certain sense in which we spend our entire lives thinking we've reached the bottom of our hearts and finding it is a false bottom. Mature Christians are not people who have completely hit the bedrock. I do not believe that is possible in this life. Rather, they are people who know how to keep drilling and are getting closer and closer.” ~ Tim Keller, Counterfeit Gods