It is impossible for any rational creature to be happy without acting all for God. God Himself could not make him happy any other way... There is nothing in the world worth living for but doing good and finishing God's work, doing the work that Christ did. I see nothing else in the world that can yield any satisfaction besides living to God, pleasing Him, and doing his whole will.
—David Brainerd (April 20, 1718 – October 9, 1747, American missionary, particularly fruitful ministering to Delaware Indians in New Jersey).