What is prayer?

The main ends of prayer are to move God, to let Him participate in our lives, and to interest ourselves in Him. What is the meaning of praise if not to make His concern our own? Worship is an act of inner agreement with God. We can petition Him for things we need only when we are sure of His sympathy for us. To praise is to feel God’s concern; to petition is to let Him feel our concern. In prayer we establish a living contact with God, between our concern and His will, between despair and promise, want and abundance. We affirm our adherence by invoking His love.—Abraham Joshua Heschel in Moral Grandeur and Spiritual Audacity: Essays, 353