From the Desert Fathers, concerning St Anthony the Great:
One day some old men came to see Abba Anthony. In the midst of them was Abba Joseph. Wanting to test them, the old man suggested a text from the Scriptures, and, beginning with the youngest, he asked them what it meant. Each gave his opinion as he was able. But to each one the old man said, 'You have not understood it.' Last of all he said to Abba Joseph, 'How would you explain this saying?' and he replied, 'I do not know.' Then Abba Anthony said, 'Indeed, Abba Joseph has found the way, for he has said: "I do not know."From The Sayings of the Desert Fathers, tr. by Benedicta Ward, SLG.