Pekah was the 18th king of the Northern Kingdom of Israel. He was a servant of King Pekahiah but rebelled, killed Pekahiah, and became king.
[See Genealogy of the Kingdom of Israel]
2 Kings 15:23In the fiftieth year of Azariah), king of Judah, Pekahiah the son of Menahem began to reign over Israel in Samaria, and reigned two years.2 Kings 15:24And he did that which was evil in the sight of the Lord: he departed not from the sins of Jeroboam the son of Nebat, who made Israel to sin.2 Kings 15:25But Pekah the son of Remaliah, a captain of his, conspired against him, and smote him in Samaria, in the palace of the king's house, with Argob) and Arieh: and with him were fifty men of the Gileadites): and he killed him, and reigned in his room.
After Pekah became king of Israel, he formed an alliance with Rezin, king of Aram, and continuously attacked the Kingdom of Judah. First, he attacked during the time of Jotham (King of Judah).
2 Kings 15:37In those days the Lord began to send against Judah Rezin) the king of Aram, and Pekah the son of Remaliah.
After Jotham's death, he invaded again during the reign of King Ahaz.
2 Kings 16:5Then Rezin) king of Aram and Pekah son of Remaliah king of Israel came up to Jerusalem to war: and they besieged Ahaz, but could not overcome him.
Later, Pekah was killed in a rebellion by his servant Hoshea, and Hoshea subsequently became king.