The Holy Grail is a silver vessel that, according to much more ancient legends, originally held the food Jesus Christ ate at Passover dinner on the night before he died. In Malory’s book, the Holy Grail has been held in England at a castle, where it holds the power to give people around it unlimited, sumptuous food and wine. The Holy Grail’s powers, however, are directly tied to the spiritual goodness of those around it. Indeed, by the end of the book, it has been proclaimed that the Holy Grail will no longer rest in England, since its citizens are no longer holy enough.
In addition to its physical powers, the Holy Grail also allows the one who can “achieve” it to see spiritual things that are normally barred to mere mortals—to reach a level of spiritual wholeness unparalleled while still on Earth. In Malory’s book, one must be entirely pure in order to “achieve” the Grail—that is, one must be both a virgin and lacking other major sins. The quest for the Holy Grail, then, is also a quest amongst those of the Round Table to prove their spiritual worth. Like Excalibur, the Grail is a symbol of glory and honor, though one relating to spiritual rather than physical prowess.