“At that time they fortified Mount Zion with high walls and strong towers all around. This was to keep the gentiles from coming and trampling them down as they had done before. Judas stationed a garrison there to guard it. He also fortified Beth-zur to guard it. Thus the people might have a stronghold that faced Idumea.”
They also fortified the Temple by making the walls taller with towers all around it. This was to keep the gentiles from coming back to trample on them as they did before. Judas also had a guard there. He also put a guard in Beth-zur, which was about 18 miles south of Jerusalem to protect the city of David from the south side that faced Idumea.
Eugene Finnegan Bible Project 