Colossians 3:15

Rule is a sporting word. The Greek is the verb for what an umpire does — the official standing at the edge of a contested game whose call settles it. Paul is not describing an atmosphere. He is describing a decision-making authority.

That changes what the verse is for. Read alone it sounds like an instruction about your inner life: be at peace, and let that peace govern your mood. Read in place — after several verses on putting up with each other and forgiving complaints — it is obviously about a room with more than one person in it. Which also explains the clause in the middle: to which also you were called in one body. Not one soul. One body.

So the umpire is on the field precisely where two people disagree. When the argument reaches the point where somebody has to decide, the standard offered is not who is right in the abstract. It is what peace between these people requires.

That is an uncomfortable standard, because it will sometimes rule against a position you could defend.

And then, hanging off the end without explanation: and be thankful. It reads like a non sequitur until you notice how much conflict runs on quiet ingratitude — the ledger of what you have given and not been thanked for. Thankfulness drains that ledger. It is not a pleasant afterthought here. It is the maintenance work.