'It is one of the particular difficulties of meditation that our thoughts are likely to wander and go their own way, toward other persons or to some events in our life. Much as this may distress and shame us again and again, we must not lose heart and become anxious, or even conclude that meditation is really not something for us. When this happens it is often a help not to snatch back our thoughts convulsively, but quite calmly to incorporate into our prayer the people and events to which our thoughts keep straying and thus in all patience return to the starting point of the meditation.'
Dietrich Bonhoeffer, Life Together, p.65.
