One day St. Augustine was walking along the sea shore and reflecting on the matter of the Holy Trinity -- one God in three Persons and to explain it logically. Suddenly, he saw a little child all alone on the shore. The child made a hole in the sand, ran to the sea with his little shell, filled his shell with sea water, and emptied it into the hole he had made in the sand. Back and forth he went to the sea, filled his shell and poured it into the hole. Augustine said to him, “Little child, what are you doing?” He replied, “I am trying to empty the sea into this hole.”
“How do you think,” Augustine asked him, “that you can empty this immense sea into this tiny hole?” He answered, “And you, how do you suppose that with your small head you can comprehend the immensity of God?” With that the child disappeared.