1 Kings 15:17
And Baasha king of Israel went up against Judah, and built Ramah, that he might not suffer any to go out or come in to Asa king of Judah.
Cross-reference
In 1 Kings 15:21, Baasha responds to Asa's alliance by abandoning his fortification of Ramah — the immediate aftermath of the attack.
In 1 Kings 15:27, the same Baasha is introduced as the conspirator who killed Nadab to become king — providing his political background for the later attack.
In 1 Kings 12:27, Jeroboam fears Israel's allegiance to Judah — a motivation underlying the north-south hostility seen in Baasha's attack.
In 2 Chronicles 16:1-6, this same campaign is recounted, adding details about Asa's treaty with Ben-Hadad to break the siege.
2 Chronicles 11:13-17 describes priests and Levites moving to Judah to support Rehoboam — strengthening Judah and fueling northern aggression like Baasha's later attack.