'Unable' in the Bible

Then the men of Ai, looking back, saw the smoke of the town going up to heaven, and were unable to go this way or that: and the people who had gone in flight to the waste land were turned back on those who were coming after them.

And as for the Jebusites living in Jerusalem, the children of Judah were unable to make them go out; but the Jebusites are living with the children of Judah at Jerusalem, to this day.