Wash jokes

My daughter often tells me that a person goes to the market to buy a horse. The horse dealer said, if you want the horse to run, just say "My God". If he wants to stop the horse, he will say "My God". If the horse buyer wants to try, he will get on the horse and say "My God". As a result, the horse really ran away, running faster and faster, and then he quickly said "My God". The horse stopped.