David then led his troops to Jerusalem to fight against the Jebusites. "You'll never get in here," the Jebusites taunted. "Even the blind and lame could keep you out!" For the Jebusites thought they were safe.
But David captured the fortress of Zion, now called the City of David.
When the insulting message from the defenders of the city reached David, he told his own troops, "Go up through the water tunnel into the city and destroy those 'lame' and 'blind' Jebusites. How I hate them." That is the origin of the saying, "The blind and the lame may not enter the house."
References for 2 Samuel 5:8
So David made the fortress his home, and he called it the City of David. He built additional fortifications around the city, starting at the Millo and working inward.
References for 2 Samuel 5:9
And David became more and more powerful, because the LORD God Almighty was with him.