XXIII. (72) "And the fourth river," continues Moses, "is the river Euphrates." And this name Euphrates means fertility; and symbolically taken, it is the fourth virtue, namely, justice, which is most truly a productive virtue, and one which gladdens the intellect. When therefore does this happen? When the three parts of the soul are all in harmony with one another; and harmony among them is in reality the predominance of the most important; as for instance, when the two inferior parts, the passionate and the appetitive part, are disposed to yield to the superior part, then justice exists. For it is just that the better portion should rule at all times, and in all places, and that the inferior part should be ruled. Now the rational part is the better part, and the appetitive and the passionate parts are the inferior ones. (73) But when, on the contrary, passion and appetite get riotous and disobey the reins, and by the violence of their impetuosity throw off and disregard the charioteer, that is to say reason, and when each of these passions get hold of the reins themselves, then there is injustice. For it is inevitable, that through any ignorance or vice of the charioteer, the chariot must be borne down over precipices, and must fall into the abyss; just as it must be saved when the charioteer is endowed with skill and virtue.