I have been making my way through Spiritual Formation by Henri Nouwen (with Michael J. Christensen and Rebecca J. Laird. The second chapter is about prayer, and it opens with the following story:
A carpenter and his apprentice were walking together through a large forest. And when they came across a tall, huge, gnarled, old, beautiful oak tree, the carpenter asked his apprentice: “Do you know why this tree is so tall, so huge, so gnarled, so old and beautiful?”
The apprentice looked at his master and said: “No . . . why?”
“Well,” the carpenter said, “because it is useless. If it had been useful it would have been cut long ago and made into tables and chairs, but because it is useless it could grow so tall and so beautiful that you can sit in its shade and relax.”Later on in the chapter Nouwen writes:
The world says, "If you are not making good use of your time, you are useless." Jesus says: "Come spend some useless time with me." If we think about prayer in terms of its usefulness to us—what prayer will do for us, what spiritual benefits we will gain, what insights we will gain, what divine presence we may feel—God cannot easily speak to us. But if we can detach ourselves from the idea of the usefulness of prayer and the results of prayer, we become free to "waste" a precious hour with God in prayer. Gradually, we may find, our "useless" time will transform us, and everything around us will be different.
Prayer is being unbusy with God instead of being busy with other things. Prayer is primarily to do nothing useful or productive in the presence of God.
From Spiritual Formation: Following the Movements of the Spirit (pages 17, 18).