If he doesn’t whoa, then you’d better not go!
Does your horse stop immediately and easily? It is no doubt the most important basic command, as it means safety for both of you. No matter if you are mounted or on the ground, the “whoa” command is your safety net, and sometimes your emergency brake.
Teaching my horse when I say “whoa”, means stop NOW and stand – no matter what. It has saved me from certain accidents.