Judges 9:54

‘ Then he called hastily to the young man his armourbearer, and said to him, “Draw your sword and kill me, so that men may not say of me, a woman slew him.” And his young man thrust him through and he died.'

Recognising that his end was near he ordered his own armourbearer, a young man, to draw his sword and kill him. The sword would be sheathed because he was helping build up wood by the door of the tower. And the young man, recognising his predicament, for he knew that for a soldier to die at a woman's hand would be to be disgraced, did as he was bid. But the disgrace has come down in history. The young armourbearer would carry Abimelech's weapons, spears and shield, prior to a fight and would fight by his master's side.

There is possibly some kind of justice recognised by the writer in what happened to Abimelech. He who had slain his brothers on a stone, was slain by a mill-stone. And stoning was the sentence exacted on those in Israel on whom the death penalty was passed.