It's origins are uncertain, but it's likely an agricultural saying that goes back hundreds of years. Here's why:
* Horsepower: Horses were essential for farming and transportation, so a dead horse was a real loss.
* Practicality: The most practical thing to do with a dead horse was to bury it or dispose of it.
* Futility: Beating a dead horse would achieve nothing. It would be a waste of energy and pointless.
While the exact origin isn't clear, the meaning of the phrase has remained consistent: to continue an action that is no longer productive or worthwhile.
It's a great reminder to let go of things that aren't working and to focus on more fruitful endeavors.