On her ceasing to speak to me, those six young men who were engaged in building came and conveyed her to the tower, and other four lifted up the seat and carried it also to the tower. The faces of these last I did not see, for they were turned away from me. And as she was going, I asked her to reveal to me the meaning of the three forms in which she appeared to me. In reply she said to me: “With regard to them, you must ask another to reveal their meaning to you.” For she had appeared to me, brethren, in the first vision the previous year under the form of an exceedingly old woman, sitting in a chair. In the second vision her face was youthful, but her skin and hair betokened age, and she stood while she spoke to me. She was also more joyful than on the first occasion. But in the third vision she was entirely youthful and exquisitely beautiful, except only that she had the hair of an old woman; but her face beamed with joy, and she sat on a seat. Now I was exceeding sad in regard to these appearances, for I longed much to know what the visions meant. Then I see the old woman in a vision of the night saying unto me: “Every prayer should be accompanied with humility: fast, therefore, and you will obtain from the Lord what you beg.” I fasted therefore for one day.
That very night there appeared to me a young man, who said, “Why do you frequently ask revelations in prayer? Take heed lest by asking many things you injure your flesh: be content with these revelations. Will you be able to see greater revelations than those which you have seen?” I answered and said to him, “Sir, one thing only I ask, that in regard to these three forms the revelation may be rendered complete.” He answered me, “How long are you senseless? But your doubts make you senseless, because you have not your hearts turned towards the Lord.” But I answered and said to him, “From you, sir, we shall learn these things more accurately.”
Source: The Pastor (or "The Shepherd") (New Advent)