Proverbs 25:28 He that hath no rule over his own spirit is like a city that is broken down, and without walls.
Your spirit is your nonphysical being which is the seat of your emotions and character.
What happens when your spirit is not under control? Who is controlling your spirit? My husband has been reading the book, The Spirit Controlled Temperament, and it shares how when you are allowing the Spirit to control you, the positive traits win...but when your flesh is controlling you, your negative traits will be showing strong.
This verse speaks of a city broken down and without walls. Have you ever been to a city where the center has moved over time? Where it used to be the thriving downtown is now broken down and riddled with with crime and despair. What happened? The attention and care was moved to the new area and the old was left to itself. It is the same with our spirit.
The part that will be thriving is the part we are putting the effort into. Be sure to rule over your character with the right tools. Stay daily in God’s Word and grow. When you stray from it, that is what weakens you.