1 Kings 21:9 - Ellicott's Commentary On The Whole Bible

Proclaim a fast. — This might be only to cover all that was to be so foully done with a cloak of religious observance, or, perhaps more probably, to imply that some secret sin had been committed, which would draw down vengeance on the whole city, and so to prepare for the false accusation. There is a like ambiguity as to the explanation of the command, “set Naboth on high,” as either an exaltation of pretended honour, or the “lifting up his head” (Genesis 40:20) for accusation. It may be noted that the whole scheme implies a return of the people to at least the outward observance of the Law of the Lord.