In the eighteenth year of the rule of Jeroboam son of Nebat, Abijah took over the throne of Judah.
He ruled in Jerusalem three years. His mother was Maacah daughter of Absalom.
He continued to sin just like his father before him. He was not truehearted to God as his grandfather David had been.
But despite that, out of respect for David, his God graciously gave him a lamp, a son to follow him and keep Jerusalem secure.
For David had lived an exemplary life before God all his days, not going off on his own in willful defiance of God's clear directions (except for that time with Uriah the Hittite).
But war continued between Abijah and Jeroboam the whole time.
The rest of Abijah's life, everything he did, is written in The Chronicles of the Kings of Judah. But the war with Jeroboam was the dominant theme.