When did Jehoash become king of Israel, if his father reigned seventeen years from Joash’s twenty-third year?

Two features of how the kings’ reigns were counted explain the figures. First, Israel at this time counted the year in which a king came to the throne as his first year, even if only part of it remained. Seventeen years counted in this way come to about sixteen full years. Second, a king often made his son joint ruler before he died, and the son’s reign could be dated from that point.

On this reading Jehoahaz reigned from Joash’s twenty-third year until about his thirty-ninth, and Jehoash was made king beside his father about two years before that, in Joash’s thirty-seventh year. Adam Clarke (following Calmet) and John Gill both suggested this joint reign; Gill thought Jehoash may have been raised up early to help save Israel from the Syrians. The modern study of these dates by Leslie McFall, which builds on Edwin Thiele’s chronology, reaches the same answer: Jehoash became co-regent in about 799 BC and king on his father’s death in about 798/797 BC.

So the dates in 2 Kings 13 are not careless. They record a real overlap, in a way of counting that the writer’s first readers would have understood.

A copyist’s slip in verse 1

Keil and Delitzsch, and Barnes, thought that ‘twenty-third’ in 2 Kings 13:1 had been miscopied for ‘twenty-first’ or ‘twenty-second’, because Jehu’s twenty-eight years (2 Kings 10:36), counted from Joash’s accession in Jehu’s seventh year, run out around Joash’s twenty-second year. Josephus does give ‘the one and twentieth year’, and twenty-one plus sixteen full years lands exactly on the thirty-seventh. The Hebrew text as we have it, however, reads twenty-three.

The dates of the kings of Israel and Judah are among the hardest in the Old Testament, and Christian chronologists do not all reconstruct them in the same way.