Charles Ellicott Commentary 1 Kings 16:19

"for his sins which he sinned in doing that which was evil in the sight of Jehovah, in walking in the way of Jeroboam, and in his sin which he did, to make Israel to sin." — 1 Kings 16:19 (ASV)

In walking in the way of Jeroboam.—The use here of this constantly-recurring phrase probably indicates only the historian’s sense of the curse lying on the whole kingdom from its idolatry, which Zimri did not attempt to repudiate; unless, perhaps, his conspiracy had clothed itself under pretence of a righteous zeal for the fulfilment of the prophecy of Jehu (1 Kings 16:3–4), and had thrown off the religious pretence after the deed was done. For otherwise, he had no time for “walking in the way of Jeroboam.”