He that hath no rule over his own spirit is like a city that is broken down, and without walls.
– Proverbs 25:28
This chapter ends with an obvious proverb comparing the lack of self-control to a city without defenses. The genius of the simile is that the city is not merely without walls, but it is broken down, or broken through. A man with no self-control has been overcome and has no resistance so he is vulnerable.