BibleTools.info

This verse explains the purpose of both the present and the former division of Abimelech‘s forces into several companies, namely, that while some of the companies attacked the men of Shechem in the field, another company, starting from their ambush, might occupy the approach to the city gate, and so cut off their retreat.

Abimelech intended to punish the Schechemites for slighting him now, but God punished them for their serving him formerly in the murder of Gideon's sons. When God uses men as instruments in his hand to do his work, he means one thing, and they another. That, which they hoped would have been for their welfare, proved a snare and a trap, as those will certainly find, who run to idols for shelter; such will prove a refuge of lies.