Of the infirmity of forgetfulness, and how we ought not to despond because of it.
A certain brother said to one of the elders, "Lo, my father, I frequently consult the elders, and they give me advice for the salvation of my soul, yet of all that they say to me I can remember nothing." Now it happened that there were two vessels standing empty beside the old man to whom he spoke. He therefore said to the brother, "Go, take one of the vessels. Put water in it. Wash it, and pour the water out of it again. Then put it back, clean, into its place. The brother did so. Then said the old man, "Bring both vessels here. Look at them carefully, and tell me which is the cleaner." "Surely," said the brother, "that is the cleaner which I washed with the water." Then said the old man to him again, "Even so it is, my son, with the soul which frequently hears the words of God. Even although the memory retain none of them, yet is that soul purer than his who never seeks for spiritual counsel."
Reference: http://www.archive.org/details/wisdomofdesert00birmrich