2 Kings 15:30

Hosea made a conspiracy against Pekah, and smote him It is probable that the people were provoked at him for leaving them exposed to a foreign enemy, while he invaded Judah; and that Hosea took advantage of their discontent and disgust to seize and slay him. Thus Pekah's treason and violence returned upon himself at last. And reigned in his stead in the twentieth year of Jotham The meaning is, that he began his reign in the twentieth year after the beginning of Jotham's reign; or, which is the same thing, in the fourth year of Ahaz, son of Jotham.