2 Chronicles 11:17
So they strengthened the kingdom of Judah, and made Rehoboam the son of Solomon strong, three years: for three years they walked in the way of David and Solomon. So they strengthened the kingdom of Judah, and made Rehoboam the son of Solomon strong, three years: for three years they walked in the way of David and Solomon.
Judah and Rehoboam were strengthened for three years, the first three years of his reign, while the people walked in the way of David and Solomon, and that period gave stability to Rehoboam as well as strength to the kingdom. That strength came because the people followed God and recognized Him as supreme ruler, not merely from fortified cities and supplies. God-fearing people from the northern tribes who set their hearts to seek the Lord came to Jerusalem to worship and joined Judah and Benjamin, and by joining them strengthened the kingdom and Rehoboam. During this time Rehoboam at times tried to serve God and was given a measure of prosperity, but he was not steadfast and eventually gave in to evil influences. The evil influences to which he gave in had surrounded him from childhood.