Just before this excerpt, Miller writes about how busy Jesus' life was, how his family even attempted "to stage an intervention because he is so busy." (Mark 3:20-21)
But he loves people and has the power to help, so he has one interruption after another. If Jesus lived today, his cell phone would be ringing constantly. The quest for a contemplative life can actually be self-absorbed. If we love people and have the power to help, then we are going to be busy. Learning to pray doesn't offer us a less busy life; it offers us a less busy heart. In the midst of outer busyness we can develop an inner quiet. Because we are less hectic on the inside, we have a greater capacity to love... and thus to be busy, which in turn drives us even more into a life of prayer.