Abijah died and was buried with his ancestors in the City of David. His son Asa became the next king. For ten years into Asa's reign the country was at peace.
Asa was a good king. He did things right in God's eyes.
He cleaned house: got rid of the pagan altars and shrines, smashed the sacred stone pillars, and chopped down the sex-and-religion groves (Asherim).
He told Judah to center their lives in God, the God of their fathers, to do what the law said, and to follow the commandments.
Because he got rid of all the pagan shrines and altars in the cities of Judah, his kingdom was at peace.
Because the land was quiet and there was no war, he was able to build up a good defense system in Judah. God kept the peace.
Asa said to his people, "While we have the chance and the land is quiet, let's build a solid defense system, fortifying our cities with walls, towers, gates, and bars. We have this peaceful land because we sought God; he has given us rest from all troubles." So they built and enjoyed prosperity.
Asa had an army of 300,000 Judeans, equipped with shields and spears, and another 280,000 Benjaminites who were shield bearers and archers. They were all courageous warriors.
Zerah the Ethiopian went to war against Asa with an army of a million plus 300 chariots and got as far as Mareshah.