God sent a spirit to stir up hostility between Abimelech and the leaders of Shechem. He made the leaders of Shechem disloyal to Abimelech.
TSK
TSK · 2 Chronicles 18:21
مراجع Treasury of Scripture Knowledge في NET.
The LORD said,‘Who will deceive King Ahab of Israel, so he will attack Ramoth Gilead and die there?’ One said this and another that.
So the LORD said to Satan,“All right then, everything he has is in your power. Only do not extend your hand against the man himself!” So Satan went out from the presence of the LORD.
He loved to curse others, so those curses have come upon him. He had no desire to bless anyone, so he has experienced no blessings.
We are from God; the person who knows God listens to us, but whoever is not from God does not listen to us. By this we know the Spirit of truth and the spirit of deceit.
and, by the signs he was permitted to perform on behalf of the beast, he deceived those who live on the earth. He told those who live on the earth to make an image to the beast who had been wounded by the sword, but still lived.