Jamieson, Fausset and Brown on 1 Kings 16:7

7. also by the hand of the prophet Jehu--This is not another prophecy, but merely an addition by the sacred historian, explanatory of the death of Baasha and the extinction of his family. The doom pronounced against Jeroboam (1Ki 14:9), did not entitle him to take the execution of the sentence into his own hands; but from his following the same calf-worship, he had evidently plotted the conspiracy and murder of that king in furtherance of his own ambitious designs; and hence, in his own assassination, he met the just reward of his deeds. The similitude to Jeroboam extends to their deaths as well as their lives--the reign of their sons, and the ruin of their families.