Asa, according to the Bible, inaugurates religious reforms, such as banning male cult prostitutes and the worship of the Canaanite goddess Asherah, consort of El, that had been sponsored by his mother, Maachah, the queen regent.

After a period of intermittent warfare between Judah and Israel, Judah enters into an alliance with the growing kingdom of Aram Damascus, by which the latter attacks northern Israel, thus relieving pressure on Judah.

Asa of Judah, taking advantage of thirty-five years of peace, has revamped and reinforced the fortresses originally built by his grandfather Rehoboam.

An invasion by the Egyptian-backed chieftain Zerah the Ethiopian (who, given the time frame with Asa's reign, may either be Pharaoh Osorkon II or Osorkon I) and his million men and three hundred chariots is defeated by Asa's five hundred and eighty thousand men (these figures come from 2 Chronicles) in the Valley of Zephath, near Mareshah (2 Chronicles 14:9-15).

The Bible does not state whether Zerah was a pharaoh or a general of the army.

The Ethiopians were pursued all the way to Gerar, in the coastal plain, where they stopped out of sheer exhaustion.

The resulting peace will keep Judah free from Egyptian incursions until the time of Josiah, some centuries later.

In Asa's 36th year, King Baasha of Israel attacks the Kingdom of Judah (2 Chronicles 16:1; the Seder Olam and some later commentators take this as the thirty-sixth year since the division of the kingdom, not the thirty-sixth year of Asa's reign).

Baasha builds the fortress of Ramah on the border, less than ten miles from Jerusalem.

The result is that the capital is under pressure and the military situation is precarious.

Asa takes gold and silver from the Temple and sends them to Ben-Hadad I, king of Aram Damascus, in exchange for the Damascene king canceling his peace treaty with Baasha.

Ben-Hadad I attacks Ijon, Dan, and many important cities of the tribe of Naphtali, and Baasha is forced to withdraw from Ramah.

Asa tears down the unfinished fortress and uses its raw materials to fortify Geba and Mizpah, on his side of the border (2 Chronicles 16:1-7).