"A man without self-control is like a city broken into and left without walls"
~Proverbs 25:28

What is self-control? It is a governance or prudent control of one's desires, cravings, impulses, emotions and passions. It is saying no when we should say no. It is moderation in legitimate desires and activities, and absolute restraint in areas that are clearly sinful.
~Jerry Bridges, Respectable Sins: Confronting the Sins We Tolerate