What ideals can you infer from Sir Gawain's distress at the end of the poem, even after he has withstood the blow of the ax?

Gawain is harsher on himself than the Green Knight is on him. Gawain curses his cowardice and covetousness and rejecting the green sash which made him guilty. The Green Knight forgives Gawain, urges him to keep the sash as a token of their struggle, and invites him back to the castle to celebrate the New Year. Gawain declines, sends his wishes to the two noble ladies, and laments on four Biblical figures (Adam, Solomon, Samson, and David) who were all ruined by the wiles of a lovely woman. He agrees to keep the girdle to remind himself of the "fault and frailty of the foolish flesh"