Vana Parva 198.8

When proceeding, another man desirous of getting a horse, also came to him. He said to the Brahmana, "On my return I shall give (you the horse).” But the Brahmana said, "Give it to me without delay.” He gave the Brahmana the only horse he had. He, then himself seizing the yoke of the car, began to drag it. He said, “There is now nothing (to give) to the Brahmanas."