These knightly virtues are explained in lines 619–665 of Sir Gawain and the Green Knight. Gawain bears the sign of the pentangle on his shield, each point of which represents a different set of five virtues. These are the "five-fold" gifts Gawain bears.

The first five are his five senses (Gawain is "faultless" in his "five wits"); the second five are his five fingers, or his personal strength, which he "failed at no time"; the third five are the five wounds of Christ on the cross (the nail wounds on Christ's hands and feet and the spear wound that pierced his side); the fourth five are the five joys of the Virgin Mary (the Annunciation, Nativity, Resurrection, Ascension, and Assumption); the fifth five are the knightly values of generosity, friendship, chastity, chivalry, and piety.

Gawain's adventure with the Green Knight becomes a test of these final five virtues—chastity and chivalry, in particular—as he ultimately learns that his own desire to live causes him to make compromises, and though he is an overall virtuous knight, his will to survive will always prevail and cause him to err, however slightly.

Sir Gawain finds that he must compromise his virtues when Sir Bertilak invites him to stay at his castle. Bertilak proposes a game in which each man will present to the other what he has "gained" that day. While Bertilak is out each day hunting, his beautiful wife attempts to seduce Gawain, who is torn between his duty to accept the hospitality of his hosts and his desire to remain chaste. By outright refusing Lady Bertilak, Gawain would be violating the chivalric code, offending his generous host. And yet accepting the lady's offer would betray his vow of chastity as well as fail and disrespect his other host, Lord Bertilak. In an attempt to do the least amount of harm, Gawain says he will not lay with Lady Bertilak, but he will exchange kisses with her.

Each night, while Bertilak gives Gawain the game he has "gained" that day, Gawain—trying to be truthful, honorable, and courteous—gives him back his wife's kisses. Later, the Green Knight, who was earlier disguised as Lord Bertilak, knows of his wife's kisses and congratulates Gawain in his efforts to honor all aspects of the five virtues. However, Gawain had not disclosed to Lord Bertilak the green girdle that Lady Bertilak had given Gawain to protect him from harm. For this, the Green Knight delivers a nick to Sir Gawain's neck, giving him the appropriate punishment for faltering and valuing his life above virtue.