Judges 1:8
Now the children of Judah had fought against Jerusalem, and had taken it, and smitten it with the edge of the sword, and set the city on fire. Now the children of Judah had fought against Jerusalem, and had taken it, and smitten it with the edge of the sword, and set the city on fire.
Judges 1:8 stands in the introduction to the book in chapters 1, 2, and 3:1-6, which comes sometime after the death of Joshua. It opens a new period in Israel's history after the people had been freed from oppression, when they were free to choose obedience or self-will. That introduction shows that Israel had not possessed all the country.
It shows Israel's failure to carry out the instructions God gave, their consequent captivity, and the help that came to them through the judges, or saviours, whom the Lord raised up for them. The verse records that the children of Judah fought against Jerusalem, and had taken it, and smitten it with the edge of the sword, and set the city on fire, identifying Jerusalem as a city in Judah. Judah was the first tribe to capture Jerusalem from the Jebusites, and this conquest may explain why the city, though assigned to Benjamin, came to be associated with Judah. The reference helps establish that Jerusalem lay within Judah, the tribe associated with the place God chose for his sanctuary; it does not call Judah or the church the sanctuary.