In Volume 2, Book 17, Chapter 2, Galahad, Sir Bors, Percivale, and a woman who turns out to be Percivale's sister all find an empty ship. Letters they find at the back of the ship use a metaphor to personify the concept of faith:
Thou man, which shall enter into this ship, beware thou be in steadfast belief, for I am Faith, and therefore beware how thou enterest, for and thou fail I shall not help thee.
This ship is faith, and if the knights are not faithful, the ship will be wrecked. The idea that a ship can symbolize faith comes from the Bible, in which the apostle Paul tells Timothy that people who have lost their faith are spiritually shipwrecked. Paul's representation of faith as a ship is a metaphor, not personification. Malory is using this metaphor, but he also allows the ship, "Faith," to speak for itself. Personified, it promises to keep the knights afloat in exchange for their "steadfast belief."
By personifying Faith in this way, Malory emphasizes that these knights have an obligation to their faith just as they have an obligation to Arthur or to one another. Their covenant with Faith is what will keep them afloat as they try to reach the Sangreal. Breaking their promises to Faith may or may not kill them, but it will certainly end their journey toward the Sangreal, which requires moral purity to be achieved. By turning the ship of faith into a literal ship with which the knights have a contract, Malory emphasizes their physical journey to the Sangreal as an allegory for the spiritual journey to prove themselves worthy for heaven. If they fail in one of these journeys, they will fail in the other.
