Charles Ellicott Commentary 1 Kings 16:9

"And his servant Zimri, captain of half his chariots, conspired against him. Now he was in Tirzah, drinking himself drunk in the house of Arza, who was over the household in Tirzah:" — 1 Kings 16:9 (ASV)

Drinking himself drunk. —There seems an emphasis of half-contemptuous condemnation in the description of Elah’s debauchery, evidently public, and in the house of a mere officer of his household, while war was raging at Gibbethon. On the other hand, Zimri—noted emphatically as his servant—was apparently the high officer left in special charge of the palace and the king’s person, while the mass of the army was in the field. Therefore, his name passed into a proverb for unusual treachery. (See 2 Kings 9:31.)