Before he united ancient Israel under one, undivided throne, King David had to conquer the Jebusite stronghold on a hill later renamed the City of David, located in the modern-day city of Jerusalem. The Jebusites, the Bible relates, were so confident in their defense against David’s attack that they even taunted the mighty king, saying the blind and lame could sufficiently defend the city (2 Samuel 5:6).
This angered David. He challenged his top military generals by offering command of his army to the warrior who could successfully capture the fortified stronghold. The Bible says Joab coordinated the sneak attack on the Jebusite city and that a water conduit—tsinnor in Hebrew—factored into the successful conquest (see 2 Samuel 5:8).