Concerning the Ten Commandments, which are the Heads of the Law (81-85)

Therefore, God, removing out of his sacred legislation all such impious deification of undeserving objects, has invited men to the honour of the one true and living God; not indeed that he has any need himself to be honoured; for being all-sufficient for himself, he has no need of any one else; but he has done so, because he wished to lead the race of mankind, hitherto wandering about in trackless deserts, into a road from which they should not stray, that so by following nature it might find the best end of all things, namely, the knowledge of the true and living God, who is the first and most perfect of all good things; from whom, as from a fountain, all particular blessings are showered upon the world, and upon the things are people in it.

Having now spoken of the second commandment to the best of our ability, let us proceed to investigate the one which follows with accuracy, as is pointed out by the order in which they come.

The next commandment is, "not to take the name of God in vain." Now the principle on which this order or arrangement proceeds is very plain to those who are gifted with acute mental vision; for the name is always subsequent in order to the subject of which it is the name; being like the shadow which follows the body.

Having, therefore, previously spoken of the existence of God, and also of the honour to be paid to the everlasting God; he then, following the natural order of connection proceeds to command what is becoming in respect of his name; for the errors of men with respect to this point are manifold and various, and assume many different characters.

That being which is the most beautiful, and the most beneficial to human life, and suitable to rational nature, swears not itself, because truth on every point is so innate within him that his bare word is accounted an oath. Next to not swearing at all, the second best thing is to keep one’s oath; for by the mere fact of swearing at all, the swearer shows that there is some suspicion of his not being trustworthy.

Let a man, therefore, be dilatory, and slow if there is any chance that by delay he may be able to avoid the necessity of taking an oath at all; but if necessity compels him to swear, then he must consider with no superficial