The blind and the crippled
"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.” (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.”) After capturing the fortress, David lived in it and named it “David's City”."
~ 2 Samuel 5.6-9 GNB
The Jebusites built a mighty fortress. It was so well protected that they got arrogant. They thought they did not need to do much - the blind and the crippled could not fight an enemy, much less a strong enemy, so they said "even the blind and the crippled could keep you out."
But the LORD handed the fortress to David.
During Jesus' time on earth, he ministered many times to the blind and the crippled. The Gospel recorded many occasions where Jesus made the blind see and the crippled walk. An astute Jew of that time would be reminded of David's story above.
Lesson 1: Do not be arrogant. Even the blind and the crippled can bring you down.
Lesson 2: The blind and the crippled can fight for the LORD. Take care of them.