Where did the phrase hold your horses come from?

Answer 1

This comes from horse racing. They used to not have racing gates, and the horses would of course, as they do now, get very excited. So the people there would say to the track helpers, "hold your horses" because the horses were excited and they didn't want them to get away.

Answer 2

it came from the old west saying stop you horses

Answer 3

They are asking you to hold your horses and not go anywhere. Horses are often champing at the bit and ready to race off, this means slow down and wait until we get thing figured out.