In Sir Gawain and the Green Knight, Gawain encounters an immortal being referred to as the Green Knight. From the moment the Green Knight barges into King Arthur's court, Sir Gawain is not only thrust into a journey that will define him as a knight, but he is exposed to several important lessons - all of which are taught by the GreenKnight. In Sir Gawain and the Green Knight, the Green Knight teaches Gawain lessons of respect and accomplishment, mortal humility, and the virtue of understanding a challenge before accepting it.

The first lesson taught to Gawain by the GreenKnight is one of respect and accomplishment. At the time that the dual with the GreenKnight is first proposed, Sir Gawain is one of the lesser knights of King Arthur's court - having not had the opportunity to prove his worth. Upon considering the GreenKnight's challenge, he accepts, acknowledging, "I am the weakest, I know, and the least wise,/ and cling least to my life, if anyone wants the truth,/ but as you are my uncle whom I live to praise/...I have asked this of you first, and beg you to grant it" (Sir Gawain and the Green Knight 354-356, 359). By saying this, it is evident that Gawain understands that strength and wisdom are acquired by knightly tasks (such as a dual with the Green Knight) and respect and honor are bestowed upon a knight if they bring praise to King Arthur's court and name. This same sort of honor can be seen within the ritual of Gawain's departure one year after the challenge had been accepted. His armor is more a piece of art than a tool of war, with, "The least of his latchet of its fastenings glittered with gold," (591) and his departure is such that, "he comes to the King and to his companions, takes his leave formally of lords and ladies, and they kissed him and walked with him and commended him to Christ" (594-596). The task that Gawain accepted has been noticed by the entire community, and they all honor him on his departure.

Perhaps no single action mirrors more clearly the honor bestowed upon a knight for engaging in a great task than the way in which the court reacted upon Gawain's return. Once Gawain tells his story of the Knight and informs the court about the green belt he wore, "Each knight of the brotherhood, should have a baldric,/ a bright green sash at a slant around him/ worn for the sake of the knight, the way he did" (2516-2518). By performing the great task of fighting the GreenKnight and returning alive, Sir Gawain has earned the respect and praise of King Arthur's court. Honor and storied immortality is not given to knights, it is earned. Gawain could not have learned or achieved this without the GreenKnight.

The second lesson taught to Gawain by the Green Knight is one of mortal humility. While on his journey to the Green Chapel, Sir Gawain rests for several days at the castle of a lord who says to Gawain, "let us have an agreement,/ whatever I take in the wood will be yours,/ and in exchange you will give me whatever you may acquire" (1105-1107). Sir Gawain remains faithful to this agreement for the first two days. On the third day of his time at the castle however, the lady of the castle presents Sir Gawain with her belt, saying, "For if a man has this green belt fastened around him,/ as long as it is knotted about his waist/ there is no knight under heaven who can cut him down" (1851-1853). Sir Gawain takes the belt and, with his dual with the Green Knight first and foremost in his mind, fails to offer it as a gift to the lord of the castle.

Upon his arrival at the Green Chapel, the Knight takes three swings at the neck of Sir Gawain. With the first two swings, he stops just before he would have hit Sir Gawain - sparing him for each of the two days that he was true to his pact at the castle. On the third swing however, the Knight nicks Sir Gawain's neck with the ax, saying, "You failed at number three/ which you got the cut for./ For the braided belt you are wearing belongs to me" (2356-2358). However, the Knight then goes on to proclaim, "I am convinced now/ that you must be the most perfect knight ever to walk the earth" (2362-2363). The Green Knight realizes that being chivalrous does not require being suicidal. Sir Gawain possesses the mortal instinct of wishing to stay alive. Though Sir Gawain is ashamed of his actions, his humanly short-coming in the dual with the Green Knight provides him the humility needed to truly be one of the greatest and most noble nights of all time.

The final, and perhaps the most obvious and "real life applicable", lesson taught to Gawain by the Green Knight is one of understanding the challenge ahead before diving in head first. When the Green Knight entered King Arthur's court, his appearance was peculiar, to say the least. Not only did he stand at a massive height, but, "he wore not helmet and no chain either,/ nor any breastplate, nor brassarts on his arms,/ he had no spear and no shield for thrusting and striking" (203-205). If his appearance alone was not strange enough, the nature of his proposal was very different from that of a normal dual. Instead of extending the challenge of a typical fight on the court's floor, the Green Knight says, "I shall take a stroke from him [the challenger] on this floor, without flinching./ Then you must grant me the right to give him one in return/ without resisting" (294-296). The nature of the Green Knight's appearance and proposal should have led Gawain to ponder some questions about the challenge and the challenger before he so eagerly accepted the task. If Sir Gawain had asked the appropriate questions before committing to combat with the Green Knight, he may not have found himself in the bizarre situation of having to take a blow from an immortal knight.

In Sir Gawain and the Green Knight, the Green Knight illustrates to Gawain the importance of respect and accomplishment through action. Through their encounters, he teaches Gawain the existence (and necessity) of mortal humility. By accepting the Green Knight's challenge without asking any of the necessary questions, Sir Gawain is taught the lesson of understanding. These three lessons - though painful and morally crushing at the time of their teaching - all will contribute to make Gawain a better, stronger, and more chivalrous knight. Through the Green Knight serves as the antagonist in Sir Gawain and the Green Knight, the lessons that he teaches Gawain make the experience far more positive than negative. Gawain's experience with the Green Knight helps to shape him. Who knows what Gawain would have been if he refused to stand up.