KJV:
And David said on that day, Whosoever getteth up to the gutter, and smiteth the Jebusites, and the lame and the blind, that are hated of David's soul, he shall be chief and captain. Wherefore they said, The blind and the lame shall not come into the house.
NKJV:
Now David said on that day, 'Whoever climbs up by way of the water shaft and defeats the Jebusites (the lame and the blind, who are hated by David's soul), he shall be chief and captain.' Therefore they say, 'The blind and the lame shall not come into the house.'
NIV:
On that day David had said, 'Anyone who conquers the Jebusites will have to use the water shaft to reach those 'lame and blind' who are David's enemies.' That is why they say, 'The 'blind and lame' will not enter the palace.'
Interpretation:
The verse refers to the Jebusites as the lame and blind, using their handicaps as a description. The verse shows that handicaps were sometimes used as insults. The verse teaches that David's enemies were described by their physical limitations. Handicaps were seen as weaknesses in battle. The verse reflects the cultural view of handicaps at that time.