What is Preaching To The Choir?
1.
Preaching to the choir means you are trying to make believers out of people who already believe, or convince people who are already convinced.
"We could start a new tradition, Birthdays without Boyfriends. It could work."
"Preachin' to the choir here baby."
2.
Extolling/defaming a cause to people convinced of it's greatness/horridness. Etymology is obviously from
Playmate: Sex sells
Hugh H: Preaching to the choir.