In Boorman's telling, the Grail appears quite suddenly, and eventually cures the ailing Arthur and brings nourishment back to the land and the people, even as Arthur rides out to meet doom in his battle against Mordred. By Tennyson's telling the Grail inspires a religious ecstasy and appears only to the most pure. It has a habit of taking knights out of court and out of their armor for the humble attire and life of the monk.
I was rebuked by a leper for my contempt of him, not seeing my scorn as unchivalrous and unbecoming of a knight, but especially of one seeking the divine blessing of the Grail.
Ultimately I recognized my failure and came to know the Grail, and this brought great joy to me and those who dwell with me in my hall and castle. But will this fulfillment reach beyond the few knights who know it and sustain the land? Who will keep the vigil for the safety of England? No Saxon will acknowledge the Grail, or even our Lord Christ. Who will stand against the tide of rivalry if our very best are busy fasting and meditating?
Nonetheless, the Grail stands as a great asset to our moral vitality. Though one may have to stand against the wicked, excellence of spirit, and charity, and virtue must not be abandoned. If the Grail has shown us nothing else it is this. He who grips the sword too tightly will surely be slain by it, and no armor is stout enough to withstand all the iniquities of this world.