How then do you pray?

The Afterward in 'The Only Necessary Thing,' various writings from Henri Nouwen, contains this little story about "The Three Monks of Tolstoy":

Three Russian monks lived in a faraway island. Nobody ever went there, but one day their bishop decided to make a pastoral visit. When he arrived he discovered that the monks didn't even know the Lord's Prayer. So he spent all his time and energy teaching them the "Our Father" and then left, satisfied with his pastoral work. But when his ship had left the island and was back in the open sea, he suddenly noticed the three hermits walking on the water - in fact, they were running after the ship! When they reached it they cried, "Dear Father, we have forgotten the prayer you taught us." The bishop, overwhelmed by what he was seeing and hearing, said, "But, dear brothers, how then do you pray?" They answered, "Well, we just say, 'Dear God, there are three of us and there are three of you, have mercy on us!" The bishop, awestruck by their sanctity and simplicity, said, "God back to your island and be at peace."