And choose, if you like, any art you please, whether trifling or important, and the man, too, who is most excellent, and most highly thought of in regard of his skill in it,
 Genesis xxvi. 32. 
 
and then consider if the professions held out by the art are equal to the performances of the artist; for if you duly examine the matter, you will find that the performance falls short of the profession, not by a small, but by a vast distance, it being almost impossible for a man to be perfect in any art whatever, which is in continual motion like a fountain, and is constantly pouring forth various species of all kinds of speculations. On this account, it is most appropriately denominated an oath, being the most certain sign of faith, comprehending also the testimony of God: for as he who swears, calls God to be a witness to a matter concerning which a question is raised, so it is not possible to swear so truly about any matter, as to the fact that the perfection of no art whatever can be found in the artist who professes it.
 And the same assertion holds good also with respect to all the other powers which exist in us, or very nearly so; for, as they say, that no water was found in the well which had been mentioned, so also neither was there the faculty of seeing in the eyes, or that of hearing in the ears, or that of smelling in the nostrils, or, in short, any one of the senses in its corresponding organ; and similarly in the mind, there was not the faculty of comprehension. For how could it have happened that any one should have made a mistake in what he saw, or in what he heard, or in what he understood, if the comprehensions of each of these faculties had been well established, and if they had had a trustworthy nature of themselves without God implanting accuracy in them?
 Having now, therefore, discussed the place sufficiently in which the tree flourishes, let us now, in conclusion, examine also the subject of the fruit: Now, what the fruit is, Moses will tell us himself: "For the Lord God everlasting," says he, "called it by its name." Genesis xxL 33.