 A person is called to give witness, in order that he may make known the truth about what is alleged. Now there are two ways in which God makes known whether the alleged facts are true or not. In one way He reveals the truth simply, either by inward inspiration, or by unveiling the facts, namely, by making public what was hitherto secret: in another way by punishing the lying witness, and then He is at once judge and witness, since by punishing the liar He makes known his lie. Hence oaths are of two kinds: one is a simple contestation of God, as when a man says “God is my witness”, or, “I speak before God”, or, “By God”, which has the same meaning, as Augustine states [*See argument On the contrary]; the other is by cursing, and consists in a man binding himself or something of his to punishment if what is alleged be not true. (ibid., Reply Obj. 3)