The Mystery of the Trinity

There is a story that St. Augustine was walking on the beach contemplating the mystery of the Trinity. Then he saw a boy in front of him who had dug a hole in the sand and was going out to the sea again and again and bringing some water to pour into the hole. St. Augustine asked him, “What are you doing?” “I’m going to pour the entire ocean into this hole.” “That is impossible, the whole ocean will not fit in the hole you have made” said St. Augustine. The boy replied, “And you cannot fit the Trinity in your tiny little brain.” The story concludes by saying that the boy vanished because St. Augustine had been talking to an angel.

From Volume 5 of The Golden Legend by Jacobus de Voragine