God sent an evil spirit between Abimelech and the men of Shechem; and the men of Shechem dealt treacherously with Abimelech:
"Strewing the ruined city with salt [Judges 9:45], which only occurs here, was a symbolical act, signifying that the city was to be turned for ever into a barren salt desert. Salt ground is barren desert (Job xxxix. 6, [Psalms] cvii. 34)." [Note: Keil and Delitzsch, p. 370.] 