Judges 9:45
And Abimelech fought against the city all that day; and he took the city, and slew the people that was therein, and beat down the city, and sowed it with salt. And Abimelech fought against the city all that day; and he took the city, and slew the people that was therein, and beat down the city, and sowed it with salt.
Abimelech was the son of Gideon's maidservant, and he had Gideon's sons slain so that he himself might become ruler of Israel. In doing so he gathered worthless followers about him. Jotham's parable of the trees in the same chapter exposes the folly of Shechem's choice of such a man.
The verse records that Abimelech fought against Shechem all that day, then took the city, slew the people that were therein, beat down the city, and sowed its site with salt, an utter destruction. The sowing of the ground with salt was a sign of lasting desolation. The destruction included the deaths of about a thousand people associated with the city's tower.
Shechem was a very ancient place where Jacob stopped when he returned from Padan-aram to Canaan. Though beaten down by Abimelech, it was afterward rebuilt and chosen by Jeroboam for his capital. This destruction was part of God's retribution against Abimelech and the Shechemites who had supported him.
The chapter teaches that those doing the most valuable work for the Lord do not seek rule over their fellow believers. Ambition to be exalted over others shows a person is unfit to rule.