There's a story about a team that split up. A horse and rider had a very special relationship. They were bound by trust through many joyful adventures. Together they covered great distances and accomplished great things. Together they moved as one. Then, one day out in the field, something confusing happened —the horse suddenly reared, and the rider fell off. The man was angry at the horse for throwing him. And the horse— well, he felt pretty skittery after that when he saw the man approach.
Sad. Because it wasn't the horse's fault, or the rider's either. It was something neither one of them had even noticed. A little serpent had slipped in, bitten the horse's heel, and slithered away unseen.
Is such an incident implied by this short Bible verse: "Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward"? Gen. 49:17.