The time came when King David and his men set out to attack Jerusalem. The Jebusites, who lived there, thought that David would not be able to conquer the city, and so they said to him, "You will never get in here; even the blind and the crippled could keep you out." 1
References for 2 Samuel 5:6
1.6-10 1 S 31.1-6; 1 Ch 10.1-6.
(But David did capture their fortress of Zion, and it became known as "David's City.")
That day David said to his men, "Does anybody here hate the Jebusites as much as I do? Enough to kill them? Then go up through the water tunnel and attack those poor blind cripples." (That is why it is said, "The blind and the crippled cannot enter the Lord's house.")
References for 2 Samuel 5:8
After capturing the fortress, David lived in it and named it "David's City." He built the city around it, starting at the place where land was filled in on the east side of the hill.
He grew stronger all the time, because the Lord God Almighty was with him.