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 BrainerdIn prayer I was exceedingly enlarged, and my soul was as much drawn out as I ever remember it to have been in my life. I was in such anguish, and pleaded with so much earnestness and importunity, that when I rose from my knees I felt extremely weak and overcome; I could scarce walk straight; my joints were loosed; the sweat ran down my face and body; and nature seemed as if it would dissolve.
David Brainerd