1 Kings 15:25 shifts the focus of attention from the kings of Judah to the kings of the northern kingdom. The narrative becomes somewhat repetitive, and one commentator, Dale Ralph Davis, calls it boring because of the monotonous repetition that shows the instability of the throne.
That cycle of instability can be described like this. A king reigns for a significant number of years, but he does evil in God’s sight and follows in the path of Jeroboam’s sin of idolatry based on the establishment of the calves at Dan and Bethel, which we have seen were meant to keep the people of Israel from going to Jerusalem to worship Yahweh in his temple. The king dies, and his son succeeds him to the throne, but after a relatively short reign the son is overthrown and murdered by someone outside the family, who kills not only his predecessor but all of the men related to the murdered monarch. The names change but the cycle continues virtually unchanged.
In 1 Kings 15:25 and 1 Kings 15:26 the writer takes his readers to the first occurrence of the repetitive cycle in the second generation. The narrative tells us of the succession of Nadab, the son of Jeroboam, to the throne of Israel. It also gives us a date stamp by placing this in the second year of Asa’s reign in Judah, and that places the event in the early part of the ninth century BC. The writer states that he followed in the evil ways of his father, who the writer says caused Israel to sin.
We must add to the previous remark something of importance. Though the sin of idolatry is serious for anyone, its guilt increases when it results in the seduction of an entire kingdom to follow in that way. All are guilty, but the leader is especially so.
25 Nadab the son of Jeroboam began to reign over Israel in the second year of Asa king of Judah, and he reigned over Israel two years.