"Sir, you are welcome in this place; I am the head of this court. They call me Arthur. Get down from your horse, I beg you, and join us for dinner, and then whatever you seek we will gladly see to" (lines 34-37).
King Arthur is inviting the Green Knight for dinner at the round table. The Green Knight refuses the invitation claiming he is there strictly for an errand and not to socialize.
Sir Gawain takes on the Green Knights errand at his own will. He strikes the Green Knights head; beheading him, but not killing him. The Green Knight takes his head in one hand and rides away on his horse saying that he wants the Knight to search for him.
"Sir Gawain laid hold of the ax and he hefted it high, if pivot foot thrown forward before him on the floor, and then, swiftly, he slashed at the naked neck" (lines 152-154).
"So he listened in silence and suffered the lady to speak, and she pressed the sash upon him and begged him to take it, and Gawain did, and she gave him the gift with great pleasure and begged him, for her sake, to not say a word" (lines 240-243).
The Knight accepts the Lord's Lady's sash and swears that he would not tell a soul of their exchange.
"'You can't be Gawain', he said 'who's thought so good, a man who's never been daunted on hill or dale! For look how you flinch for fear before anything is felt!..." (lines 262-264).
The Knight finds the Green Knight not to be in a chapel, but in a gloomy, rugged place. Finding him sharpening the blade of his ax. The Green Knight taunts the Knight.
The Green Knight strikes the Knights neck after 3 attempts. However, as hard has he tried the strike didn't do more than split the skin.
"...I owed you a stroke, and I've struck; consider yourself well paid. And now I release you from all further duties..." (lines 333-334).
After the 3 attempts the Knight and the Green Knight made amends. They embraced and then parted their own ways.
"'I've revealed too well already; but fortunate to be with you; may he who gives all honors honor you well" (line 401-402).