Indeed, there is a difference among knights, and the chivalric code certainly has its flaws. For instance, near the beginning of Le Morte d'Arthur, the reader learns that a good knight should live"to be with all ladies and to fight for their quarrels and that ever he should be courteous" (l.104). However, chivalry without a certain wisdom is not good; it is dangerous. For, to fight the quarrels of the likes of Morgan le Fay would not be noble or wise. And, while "courtly love" is chivalric, it conflicts with Christian chilvalry. Thus, Launcelot, who engages in adultery with Guinevere, alienates himself from the Christian element of chivalry. After his affair with Guinevere, he says, "now I see and understand that mine old sin hindereth me and shameth me."
Launcelot, however, does attempt to atone for his sins and does not kill men; this is in contrast to Sir Gawain, who slaughters Sir Feldenek. In addition, Sir Gawain violates the courtly and Christian chilvalric codes as one of his first acts is to decapitate a maiden.
Sir Gawain would no mercy have but unlaced his helm to have stricken off his head. Right so came his lady out of a chamber and fell over him, and so he smote off her head by misadventure (I.102)
Further, Sir Gawain is unrepentant; after a hermit warns him to atone for his sins, Gawain says, "Nay . . . I may do no penance; for we knights adventurous oft sufferen great woe and pain" (II.266). Here again he is the antithesis of Launcelot, who makes amends for his sins through many heroic deeds in Book II.