And in the blast there smote along the hall A beam of light seven times more clear than day: And down the long beam stole the Holy Grail All over covered with a luminous cloud. And none might see who bare it, and it past. But every knight beheld his fellow's face As in a glory, and all the knights arose, And staring each at other like dumb men Stood, till I found a voice and sware a vow. - Idylls of the King
Le Morte d'Arthur by Sir Thomas Malory:
"Then anon they heard cracking and crying of thunder, that them thought the place should be destroyed. In the midst of this blast entered a sunbeam more clear by seven times than ever they saw day, and all there were alighted of the grace of the Holy Ghost. Then began every knight to behold other, and either saw other, by their seeming, fairer than ever they saw afore. There was no knight might speak one word a great while, and so they looked every man on other as they had been dumb. Then there entered into the hall the Holy Grail covered with white samite, but there was none might see it, nor who bare it. And there was all the hall filled with good odours, and every knight had such meats and drinks as he best loved in this world. And when the Holy Grail had been borne through the hall, then it departed suddenly, that they wist not where it went: then had they all breath to speak. And the king yielded thanks to God, of His good grace that he had sent them. 'Certainly', said the king, 'we ought to thank our Lord Jesu greatly for that he hath shewed us this day, at the reverence of this high feast of Pentecost.'"
Embarking on the Quest
Gawain's Vow to Pursue the Quest
(Spoken at Camelot after the Grail's appearance at Pentecost; inspires the Round Table knights to embark.)
Wherefore, for my part I make this vow, to enter to-morrow without delay upon the Quest and to prosecute it for a year and a day, and longer yet if need be; and I will not return to court for any reason whatsoever until I have seen it more clearly than it has been manifested to me here, if peradventure it be destined that I can behold it. And if it be destined otherwise, I will return.
Galahad's Oath on Sacred Relics (Sworn before departing Camelot, formalizing his commitment as the destined Grail knight.)
As a loyal knight that he would pursue this Quest for a year and a day, or longer if need be, and would never return to court until he had learned the truth concerning the Holy Grail, if he could in any way do so.
Lancelot's Invocation for Protection (Exchanged with Queen Guinevere before leaving; highlights reliance on Christ's sacrifice.)
Lady, may God do so in His great pity! (In response to Guinevere's blessing: "But since go you must, go in the keeping of Him who consented to suffer on the true Cross to deliver man from eternal death. May He conduct you in safety wherever you go!")