Charles Ellicott Commentary Jeremiah 41:12

"then they took all the men, and went to fight with Ishmael the son of Nethaniah, and found him by the great waters that are in Gibeon." — Jeremiah 41:12 (ASV)

By the great waters that are in Gibeon.— Johanan and his friends had been unable to prevent the slaughter of which they had warned Gedaliah (Jeremiah 41:15), but they were not too late to avenge it. Gibeon, retaining its name with little alteration in the modern El-jibe, lay about two miles from Mizpah; so that Ishmael must have halted, thinking himself safe against attack.

On the east side of the hill on which it stands are the remains of a large tank, about 120 feet by 100. It appears as the pool of Gibeon in 2 Samuel 2:13, as the scene of a conflict between Joab and Abner. Josephus (Ant. x. 9-15) places the attack on Ishmael at the pool in Hebron, which is mentioned in 2 Samuel 4:12. This, however, would hardly have been in Ishmael’s route to the country of the Ammonites.