Keep thy heart with all diligence; for out of it are the issues of life.
Proverbs 4:23 · KJV
Ancient cities did not fall because the walls were weak. They fell because a gate was left unattended. Scripture keeps returning to this image because it is how people actually fall — not by a frontal assault on their faith, but by an unguarded entrance nobody was watching.
'With all diligence' is the language of a night watch. Deliberate, repeated, unglamorous attention. Nobody praises the guard on a quiet night, which is exactly why the guard gets tired and stops looking.
Out of the heart are the issues of life — meaning what you allow in does not stay a private matter. It becomes your speech, your decisions, your appetites, and eventually your direction.
Audit one gate today: what you watch, what you scroll, who you talk to late at night, or what you listen to on the commute. Close or change one of them.