7.
“In the second year of Joash son of Jehoahaz king of Israel reigned Amaziah the son of Joash king of Judah” (2 Kings xiv, 1).
From the death of Ahaziah to the accession of Amaziah the reigns of Israel’s kings were: Jehoram 12 years, Jehu 28 years, Jehoahaz 17 years, Joash 2 years. 12 years + 28 years + 17 years + 2 years = 59 years.
From the death of Jehoshaphat to the accession of Amaziah, Judah’s kings reigned—Joram 8 years, Ahaziah 1 year, Athaliah 6 years, Joash 40 years. 8 years + 1 year + 6 years + 40 years = 55 years.
If from the death of Ahaziah to the accession of Amaziah was fifty-nine years, and from the death of Jehoshaphat to the accession of Amaziah was fifty-five years, Jehoshaphat therefore died four years after Ahaziah died.