'Defense' in the Bible

For this is what the Lord, the God of Israel, says concerning the houses of this city and the palaces of Judah’s kings, the ones torn down for defense against the siege ramps and the sword:

Raise a war cry against her on every side!She has thrown up her hands in surrender;her defense towers have fallen;her walls are demolished.Since this is the Lord’s vengeance,take out your vengeance on her;as she has done, do the same to her.