Indulge not thyself in the passion of anger it is whetting a sword to wound thine own breast, or murder thy friend.

The saying frames anger as a self-destructive force: to “whet” (sharpen) a sword in anger is to prepare a weapon that will most likely harm the person who holds it (“wound thine own breast”) or destroy valued relationships (“murder thy friend”). The metaphor emphasizes that anger is not merely an outward-directed emotion but a practice that trains one toward violence, rash speech, and irreversible acts. Its moral logic is preventative—do not indulge the passion at all—because once anger is cultivated it becomes an instrument ready for use. The archaic diction (“thyself,” “thine”) also signals that the line likely comes from later moralizing tradition rather than a direct ancient Egyptian formulation.