John Wesley on Luke 11:15

But some said, He casteth out devils by Beelzebub - These he answers, Lu 11:17. Others, to try whether it were so or no, sought a sign from heaven. These he reproves in Lu 11:29 and following verses. Beelzebub signifies the lord of flies, a title which the heathens gave to Jupiter, whom they accounted the chief of their gods, and yet supposed him to be employed in driving away flies from their temple and sacrifices. The Philistines worshipped a deity under this name, as the god of Ekron: from hence the Jews took the name, and applied it to the chief of the devils. Mr 3:22.