This verse is nearly identical with Joshua 15:63, except in the substitution of Benjamin for Judah. Probably the original reading Judah was altered in later times to Benjamin, because Jebus was within the border of Benjamin, and neither had the Benjamites expelled the Jebusites.
Related Commentaries of Judges 1:21
Judges 1:21
21 And the children of Benjamin did not drive out the Jebusites that inhabited Jerusalem; but the Jebusites dwell with the children of Benjamin in Jerusalem unto this day.