1 Kings 14:21 - Joseph Benson’s Commentary on the Old and New Testaments

Rehoboam was forty and one years old when he began to reign Although many learned men are of opinion that there is an error in the text here in regard to the age of Rehoboam when he began to reign, and some think the reading should be twenty-one, while Houbigant, following the Seventy, reads sixteen years; yet as they do not seem to give sufficient reasons for the alteration, it is certainly safest to abide by the Hebrew text. According to this, he was born in the last year of David's life, and certainly had his education, and the forming of his mind, in the best days of Solomon; and yet, with all the advantages he enjoyed, he was a weak and inconsiderate prince, who, instead of being a blessing, proved a curse to his kingdom. Probably Solomon's defection, in the latter part of his life, did more to corrupt him than his prior wisdom and devotion had done to render him wise and virtuous. He reigned seventeen years in Jerusalem, the city, &c. Where he had opportunities in abundance to know his duty, had he but had a heart to practice it. His mother was Naamah an Ammonitess She was probably the daughter of Shobi, the Ammonite, who was so kind to David in Absalom's rebellion. And as there is reason to think Shobi had become a proselyte to the true religion, it is likely that gratitude, for his kindness moved David to take his daughter, though an Ammonitess, to be the wife of his son Solomon. It is very doubtful, however, whether ever she cordially embraced the religion of the Israelites, and as Solomon worshipped the gods of the Ammonites, among his other idols, it is not improbable that she was concerned in seducing him. None can imagine how lasting and how fatal the consequences may be, of being unequally yoked with an unbeliever.