Jamieson, Fausset and Brown on 2 Chronicles 12:13-14

13-14. Rehoboam strengthened ... and reigned--The Egyptian invasion had been a mere predatory expedition, not extending beyond the limits of Judah, and probably, ere long, repelled by the invaded. Rehoboam's government acquired new life and vigor by the general revival of true religion, and his reign continued many years after the departure of Shishak. But

he prepared not his heart to seek the Lord--that is, he did not adhere firmly to the good course of reformation he had begun, "and he did evil," for through the unhappy influence of his mother, a heathen foreigner, he had no doubt received in his youth a strong bias towards idolatry (see on 1Ki 14:21).