Charles Ellicott Commentary 2 Chronicles 12:13

"So king Rehoboam strengthened himself in Jerusalem, and reigned: for Rehoboam was forty and one years old when he began to reign, and he reigned seventeen years in Jerusalem, the city which Jehovah had chosen out of all the tribes of Israel, to put his name there: and his mother`s name was Naamah the Ammonitess." — 2 Chronicles 12:13 (ASV)

(b) SUMMING UP OF THE REIGN (2 Chronicles 12:13–16). (Compare to 1 Kings 14:21–22, 1 Kings 14:29, and 1 Kings 14:31.)

The Syriac and Arabic contain this section. Verse 13 states, So king Rehoboam strengthened himself.—After the withdrawal of Shishak. In other words, he regained strength after the crushing blow inflicted by the Egyptian invasion. (Compare the use of the same word in 2 Chronicles 13:21 and 2 Chronicles 1:1.)

And reigned—i.e., he continued to reign for twelve more years, for he reigned a total of seventeen years.

Rehoboam was one and forty ... Naamah an Ammonitess.—Word for word as in 1 Kings 14:21. (See the Notes there.)