So, when we say that piety is a ministering to God, we say that it is in some such a service as slaves discharge to their masters, who are taught to do without hesitation that which is commanded them; but, again, there will be a difference, because the masters are in need of service, but God has no such want. So that, in the case of the masters, the servants do supply that which will be of use to them, but to God they supply nothing beyond a mind imbued with a spirit of willing obedience; for they will not find anything which they can improve, since all things belonging to masters are, from the very beginning, most excellent; but they will benefit themselves very greatly by determining to become friends to God.
 I think, therefore, that enough has been now said with respect to those who appear to think that they do others good or harm. For it has been shown, that that which they think that they are doing to others, they in either case do to themselves. We will now examine the remainder of this event; the question is as follows:—"Where is Abel, thy
 
brother?" Genesis iv. 9. To which answer is made, "I do not know; am I my brother’s keeper?" It is therefore worth while to consider the question whether it can be appropriately said of God that he asks a question. For he who asks a question or puts an inquiry is asking or inquiring about something of which he is ignorant; seeking an answer through which he will know what he as yet does not know. But everything is known to God, not only all that is present, and all that is past, but also all that is to come. What need, then, has he of an answer which cannot give any additional knowledge to the questioner? But we must say that such things cannot properly be uttered by the Cause of all things, but that, as it is possible to say what is not true without lying, so it is possible for one to put a question or an interrogatory without either making inquiry or seeking for information. "Why, then," some one will say, "are such words spoken?" In order that the soul which is about to give the answer may prove by itself what it answers correctly or incorrectly, having no one else either as an accuser or an adversary.
 Since, when he asks the wise man, Where is virtue? Genesis xviii. 9. that is to say, when he asks Abraham about Sarah, he asks, not because he is ignorant, but because he thinks that he ought to answer for the sake of eliciting praise from the answer of him who speaks. Accordingly, Moses tells us that Abraham answered, "Behold, she is in the tent;" that is to say, in the soul. What then is there in this answer that contains praise? Behold, says he, I keep virtue in my house as a treasure carefully stored up, and on account of this I am immediately happy. For it is the use and enjoyment of virtue that is happiness, and not the bare possession of it. But I should not be able to use it unless you, by letting down the seeds from heaven, had yourself made virtue pregnant; and unless she had brought forth the germs of happiness, namely, Isaac. And I consider that happiness is the employment of perfect virtue in a perfect life. In reference to which he, approving of his own determination, promises that he will complete perfectly all that he asked.