1 Kings 15:1

Now in the eighteenth year of king Jeroboam the son of Nebat reigned Abijam over Judah.

Abijam began to reign over Judah in the eighteenth year of the reign of Jeroboam the son of Nebat over Israel. That dating places the verse in the period of the divided kingdom, in the history of the separate kingdoms of Judah and Israel after the revolt of the ten tribes. Within that history it belongs to the succession of the kings of Judah.

In that succession Abijam followed his father Rehoboam, coming after Rehoboam's reign and after the prophecy against Jeroboam's altar. At that time Judah comprised two and a half tribes and Israel ten tribes, with war and strife between the two divisions. The reign of Abijam thus introduced was brief and wicked.

Asa followed Abijam and ruled largely for the better. The verse stands within the account of Israel's apostasy under its kings, when the nation turned from the worship of the living God and the God-given plan of worship pointing to Christ and showing the way of salvation from sin to idolatry. The fuller account of Abijah and Asa in Judah is given in Chronicles.