Le Morte dArthur Vol. 2 Chap. 16.4
          CHAPTER IV. How the hermit expounded their advision.

        THEN spake Nacien unto Ector: Sooth it is that Launcelot and ye came down off one chair: the chair betokeneth mastership and lordship which ye came down from. But ye two knights, said the hermit, ye go to seek that ye shall never find, that is the Sangreal; for it is the secret thing of our Lord Jesu Christ. What is to mean that Sir Launcelot fell down off his horse: he hath left pride and taken him to humility, for he hath cried mercy loud for his sin, and sore repented him, and our Lord hath clothed him in his clothing which is full of knots, that is the hair that he weareth daily. And the ass that he rode upon is a beast of humility, for God would not ride upon no steed, nor upon no palfrey; so in ensample that an ass betokeneth meekness, that thou sawest Sir Launcelot ride on in thy sleep. And the well whereas the water sank from him when he should have taken thereof, and when he saw he might not have it, he returned thither from whence he came, for the well betokeneth the high grace of God, the more men desire it to take it, the more shall be their desire. So when he came nigh the Sangreal, he meeked him that he held him not a man worthy to be so nigh the Holy Vessel, for he had been so defouled in deadly sin by the space of many years; yet when he kneeled to drink of the well, there he saw great providence of the Sangreal. And for he had served so long the devil, he shall have vengeance four-and-twenty days long, for that he hath been the devil's servant four-and-twenty years. And then soon after he shall return unto Camelot out of this country, and he shall say a part of such things as he hath found

        Now will I tell you what betokeneth the hand with the candle and the bridle: that is to understand the Holy Ghost where charity is ever, and the bridle signifieth abstinence. For when she is bridled in Christian man's heart she holdeth him so short that he falleth not in deadly sin. And the candle which sheweth clearness and sight signifieth the right way of Jesu Christ. And when he went and said: Knights of poor faith and of wicked belief, these three things failed, charity, abstinence, and truth; therefore ye may not attain that high adventure of the Sangreal.