Matthew 10:25

It is enough for the disciple that he be as his master, and the servant as his lord. If they have called the master of the house Beelzebub--All the Greek manuscripts, write "Beelzebul," which undoubtedly is the right form of this word. The other reading came in no doubt from the Old Testament "Baalzebub," the god of Ekron (Kg2 1:2), which it was designed to express. As all idolatry was regarded as devil worship (Lev 17:7; Deu 32:17; Psa 106:37; Co1 10:20), so there seems to have been something peculiarly satanic about the worship of this hateful god, which caused his name to be a synonym of Satan. Though we nowhere read that our Lord was actually called "Beelzebul," He was charged with being in league with Satan under that hateful name (Mat 12:24, Mat 12:26), and more than once Himself was charged with "having a devil" or "demon" (Mar 3:30; Joh 7:20; Joh 8:48). Here it is used to denote the most opprobrious language which could be applied by one to another. how much more shall they call them of his household--"the inmates." Three relations in which Christ stands to His people are here mentioned: He is their Teacher--they His disciples; He is their Lord--they His servants; He is the Master of the household--they its inmates.

— Jamieson-Fausset-Brown Commentary (public domain)