2 Samuel 2:11-13 New Revised Standard Version (NRSV)
11 The time that David was king in Hebron over the house of Judah was seven years and six months.
The Battle of Gibeon
12 Abner son of Ner, and the servants of Ishbaal[a] son of Saul, went out from Mahanaim to Gibeon. 13 Joab son of Zeruiah, and the servants of David, went out and met them at the pool of Gibeon. One group sat on one side of the pool, while the other sat on the other side of the pool.