"Whether you turn to the right or to the left, your ears will hear a voice behind you, saying, 'This is the way; walk in it.'" Isaiah 30:21
Horses are a curious animal. They each have their own personality and level of willingness to obey. I guess you could say they are a lot like us humans actually. I learned as a youngster that the reins that are connected to the horse's bridle are the means by which they are controlled.
Some horses have to be forced to go to the right or left or to back up by pulling hard on the reins from one side or the other or straight back. They still have a mind of their own and have not been fully taught to follow their master's leading. They get confused, frustrated and down right stubborn at times and getting them to obey can often be a test of wills. These animals consistently try their owners and often make riding them a chore rather than a delight.
There are others though, those that have been completely broken, that need only a slight nudge or to simply have the reins laid over on one side of their neck or the other to move obediently to the right or to the left. The rider need only to barely lay the leather against the animal's neck to easily obtain the desired response. Slight nudges with the heels or clicking of the tongue are all that is often necessary to begin the ride. Riding these horses is simply a pleasure. No battle is necessary, the animal almost anticipates the desire of it's master. His master's will becomes his own.
Is the spiritual lesson obvious? Have you been broken before your Lord to the point that His will has become yours? Are you neck-reined?