Silently they went into the great hall and sat down in their places at the Round Table. Then King Arthur looked about him and saw that all the sieges were full, and he remembered the words of Merlin the wise enchanter.
‘Lo! now,’ said King Arthur, ‘there sits about this board the fairest company that ever the world shall see. This is the highest hour of our holy realm of Logres, the hour of the Glory of Logres.’
Even as he said these words there blew a great wind about the castle and a mighty crash of thunder shook the place; then on a sudden a sunbeam cut through the gloom from end to end of the great hall, seven times more clear than ever man saw on the brightest day of summer; and the glory of God was upon them all. Each knight looked upon one another, and each saw the other fairer than he had ever seemed before: yet none could speak a word, and they sat there at the Round Table as if they had been stricken dumb.
Then the Holy Grail entered into the hall covered in a cloth of white samite, so filled with glorious light that none might behold it. Nor could they see who carried the Holy Grail, for it seemed to glide upon the sunbeam, passing through the midst of them and filling them with the joy and peace of the fullness of God. Then on a sudden it departed from among them, and none might see where it went: but the sunbeam faded also, and they sat in silence, filled with a great peace. Only Sir Mordred hid his face in his hands, and the hot tears of shame trickled between his fingers.
Presently King Arthur said in a hushed voice:
‘Surely we ought to thank Our Lord Jesus Christ that He has sent his blessing upon us this high Feast of Pentecost.’
Roger Lancelyn Green - King Arthur and His Knights of the Round Table (Puffin, 1953)
Oh yes! Let the Grail come forth.
I have a great second-hand copy of this book with wonderful illustrations!