This from Tim Keller, a pastor at Redeemer Presbyterian Church in New York City:
Prayer is the only entryway into genuine self-knowledge. It is also the main way we experience deep change – the reordering of our loves. Prayer is how God gives us so many of the unimaginable things he has for us. Indeed, prayer makes it safe for God to give us many of the things we most desire. It is the way we know God, the way we finally treat God as God. Prayer is simply the key to everything we need to do and be in life.