2.
“Now in the eighteenth year of King Jeroboam the son of Nebat reigned Abijam over Judah” (1 Kings xv, 1).
As Jeroboam reigned 22 years, he reigned four years after the beginning of Abijam’s reign. From the beginning of Abijam’s reign, then, to the death of Ahaziah, the reigns of Israel’s kings were: Jeroboam 4 years, Nadab 2 years, Baasha 24 years, Elah 2 years, Omri 12 years Ahab 22 years, and Ahaziah 2 years. 4 years + 2 years + 24 years + 2 years + 12 years + 22 years + 2 years = 68 years.
From the beginning of Abijam’s reign to the death of Jehoshaphat the reigns of Judah’s kings were: Abijam 3 years, Asa 41 years, Jehoshaphat 25 years. 3 years + 41 years + 25 years = 69 years.
If from the beginning of Abijam’s reign to the death of Ahaziah was sixty-eight years, and from the beginning of Abijam’s reign to the death of Jehoshaphat was sixty-nine years, Jehoshaphat therefore died one year after Ahaziah died.