Preach to the converted

Pro Tip 1/3

Often used when someone insists on a point that everyone already agrees with or understands.

When the teacher kept explaining the rule, a student said, 'You're preaching to the converted.'

Pro Tip 2/3

Mainly used in casual or informal conversations, not in formal writing.

At the family dinner, Uncle Joe was preaching to the converted about the benefits of organic food.

Pro Tip 3/3

Can express mild irritation or frustration at having to hear something already accepted.

We all recycle here; you're preaching to the converted.