2 Samuel 5:6-9
    When the king and his men went to Jerusalem to attack the Jebusites who lived there, the Jebusites said to David, “You can’t get inside our city. Even the blind and the crippled can stop you.” They thought David could not enter their city. But David did take the city of Jerusalem with its strong walls, and it became the City of David.
    That day David said to his men, “To defeat the Jebusites you must go through the water tunnel. Then you can reach those ‘crippled’ and ‘blind’ enemies...”
    So David lived in the strong, walled city and called it the City of David. David built more buildings around it, beginning where the land was filled in. He also built more buildings inside the city.

1 Chronicles 11:4-8
    David and all the Israelites went to the city of Jerusalem. At that time Jerusalem was called Jebus, and the people living there were named Jebusites. They said to David, “You can’t get inside our city.” But David did take the city of Jerusalem with its strong walls, and it became the City of David.
    David had said, “The person who leads the attack against the Jebusites will become the commander over all my army.” Joab son of Zeruiah led the attack, so he became the commander of the army.
    Then David made his home in the strong, walled city, which is why it was named the City of David.  David rebuilt the city, beginning where the land was filled in and going to the wall that was around the city. Joab repaired the other parts of the city.