LXXIII. (205) They say, indeed, that an oath is a testimony borne by God concerning a matter which is the subject of doubt. But if God swears he is bearing testimony to himself, which is an absurdity. For the person who bears the testimony, and he on whose behalf it is borne, ought to be two different persons. What, then, are we to say? In the first place, that it is not a matter of blame for God to bear testimony to himself. For what other being could be competent to bear testimony to him? In the second place, He himself is to himself every thing that is most honourable–relative, kinsman, friend, virtue, prosperity, happiness, knowledge, understanding, beginning, end, entirety, universality, judge, opinion, intention, law, action, supremacy. (206) Besides, if we only receive the expression, “By myself have I sworn,” in the manner in which we ought, we shall be in no danger from sophistry. May we not, then, say, that the truth is something of this sort? None of those beings which are capable of entertaining belief, can entertain a firm belief respecting God. For he has not displayed his nature to any one; but keeps it invisible to every kind of creature. Who can venture to affirm of him who is the cause of all things either that he is a body, or that he is incorporeal, or that he has such and such distinctive qualities, or that he has no such qualities? or who, in short, can venture to affirm any thing positively about his essence, or his character, or his constitution, or his movements? But He alone can utter a positive assertion respecting himself, since he alone has an accurate knowledge of his own nature, without the possibility of mistake. (207) His positive assertion, therefore, is one which may be thoroughly trusted in the first place, since he alone has any knowledge respecting his actions; so that he very appropriately swore by himself, adding himself confirmation to his assertion, which it was not possible for any one else to do. On which account men who say that they swear by God may well be considered impious. For no man can rightly swear by himself, because he is not able to have any certain knowledge respecting his own nature, but we must be content if we are able to understand even his name, that is to say, his word, which is the interpreter of his will. For that must be God to us imperfect beings, but the first mentioned, or true God, is so only to wise and perfect men. (208) And Moses, too, admiring the exceeding excellency of the great uncreated God, says, “And thou shalt swear by his Name,”{106}{#de 6:13.} not by himself. For it is sufficient for the creature to receive confirmation and testimony from the word of God. But God is his own confirmation and most unerring testimony.