(16) However, as the true object of legislation is only perceived by a few, and most men are almost incapable of grasping it, though they live under its conditions, legislators, with a view to exacting general obedience, have wisely put forward another object, very different from that which necessarily follows from the nature of law: they promise to the observers of the law that which the masses chiefly desire, and threaten its violators with that which they chiefly fear: thus endeavouring to restrain the masses, as far as may be, like a horse with a curb; whence it follows that the word law is chiefly applied to the modes of life enjoined on men by the sway of others; hence those who obey the law are said to live under it and to be under compulsion. (17) In truth, a man who renders everyone their due because he fears the gallows, acts under the sway and compulsion of others, and cannot be called just. (18) But a man who does the same from a knowledge of the true reason for laws and their necessity, acts from a firm purpose and of his own accord, and is therefore properly called just. (19) This, I take it, is Paul's meaning when he says, that those who live under the law cannot be justified through the law, for justice, as commonly defined, is the constant and perpetual will to render every man his due. (20) Thus Solomon says (Prov. xxi:15), "It is a joy to the just to do judgment," but the wicked fear. (21) Law, then, being a plan of living which men have for a certain object laid down for themselves or others, may, as it seems, be divided into human law and Divine law. (22) By human law I mean a plan of living which serves only to render life and the state secure. (23) By Divine law I mean that which only regards the highest good, in other words, the true knowledge of God and love. (24) I call this law Divine because of the nature of the highest good, which I will here shortly explain as clearly as I can.