"You shall not work with the bechor of your bullock, and you shall not shear the bechor of your flock": R. Yehudah says: You may not work with the bechor of your bullock, but you may work with one (held in partnership) by you and others (i.e., gentiles, such animals not being subject to the law of the first-born.) "and you shall not shear the bechor of your flock": But you may shear one (held in partnership) by you and others. R. Shimon says: "You shall not work with the bechor of your bullock," but you may work with the first-born of a human being. "and you shall not shear the bechor of your flock," but you may shear the firstling of an ass.