David immediately after being anointed king of Israel, probably wished to signalize his accession by an exploit which would be popular with all Israel, and especially with Saul’s tribe, Benjamin. He discerned the importance of having Jerusalem for his capital both because it belonged as much to Benjamin as to Judah, and on account of its strong position.
Except thou take away the blind ... - Rather, “and (the Jebusite) spake to David, saying, Thou shalt not come hither, but the blind and the lame shall keep thee off,” i. e. so far shalt thou be from taking the stronghold from us, that the lame and blind shall suffice to defend the place.