This way of simple prayer, when we are faithful to it and practice it at regular times, slowly leads us to an experience of rest and opens us to God’s active presence. Moreover, we can take this prayer with us into a very busy day. When, for instance, we have spent twenty minutes in the early morning sitting in the presence of God with the words “The Lord is my Shepherd” they may slowly build a little nest for themselves in our heart and stay there for the rest of our busy day. Even while we are talking, studying, gardening, or building, the prayer can continue in our heart and keep us aware of God’s ever-present guidance. The discipline is not directed toward coming to a deeper insight into what it means that God is called our Shepherd, but toward coming to the inner experience of God’s shepherding action in whatever we think, say or do.

Henri Nouwen, The Way of the Heart, pp 82-83.