Again, there is another production of the soul formed by imaginations derived from material things, and called the knowledge of things. In reference to this we are fitly warned against inquisitiveness to correct which is the great function of temperance. Thus it is said, "Take heed lest any one seduce you by philosophy." And because the word philosophy originally means the love and pursuit of wisdom, a thing of great value and to be sought with the whole mind, the apostle, with great prudence, that he might not be thought to deter from the love of wisdom, has added the words, "And the elements of this world."  For some people, neglecting virtues, and ignorant of what God is, and of the majesty of nature which remains always the same, think that they are engaged in an important business when searching with the greatest inquisitiveness and eagerness into this material mass which we call the world. This begets so much pride, that they look upon themselves as inhabitants of the heaven of which they often discourse. The soul, then, which purposes to keep itself chaste for God must refrain from the desire of vain knowledge like this. For this desire usually produces delusion, so that the soul thinks that nothing exists but what is material; or if, from regard to authority, it confesses that there is an immaterial existence, it can think of it only under material images, and has no belief regarding it but that imposed by the bodily sense. We may apply to this the precept about fleeing from idolatry.
39. To this New Testament authority, requiring us not to love anything in this world,  especially in that passage where it is said, "Be not conformed to this world,"  -- for the point is to show that a man is conformed to whatever he loves, -- to this authority, then, if I seek for a parallel passage in the Old Testament, I find several; but there is one book of Solomon, called Ecclesiastes, which at great length brings all earthly things into utter contempt. The book begins thus: "Vanity of the vain, saith the Preacher, vanity of the vain; all is vanity. What profit hath a man of all his labor which he taketh under the sun?"  If all these words are considered, weighed, and thoroughly examined, many things are found of essential importance to those who seek to flee from the world and to take shelter in God; but this requires time and our discourse hastens on to other topics. But, after this beginning, he goes on to show in detail that the vain  are those who are deceived by things of this sort; and he calls this which deceives them vanity, -- not that God did not create those things, but because men choose to subject themselves by their sins to those things, which the divine law has made subject to them in well-doing. For when you consider things beneath yourself to be admirable and desirable, what is this but to be cheated and misled by unreal goods? The man, then, who is temperate in such mortal and transient things has his rule of life confirmed by both Testaments, that he should love none of these things, nor think them desirable for their own sakes, but should use them as far as is required for the purposes and duties of life, with the moderation of an employer instead of the ardor of a lover. These remarks on temperance are few in proportion to the greatness of the theme, but perhaps too many in view of the task on hand.
 Galatians 1:10.  Colossians 2:8.  1 John 2:15.  Romans 12:2.  Ecclesiastes 1:2, 3.  Retract. i. 7, 3: --"I found in many manuscripts the reading, Vanity of the vain.' But this is not in the Greek, which has Vanity of vanities.' This I saw afterwards. And I found that the best Latin manuscripts had vanities and not vain. But the truths I have drawn from this false reading are self-evident."
 Colossians 2:8.
 1 John 2:15.
 Romans 12:2.
 Ecclesiastes 1:2, 3.
 Retract. i. 7, 3: --"I found in many manuscripts the reading, Vanity of the vain.' But this is not in the Greek, which has Vanity of vanities.' This I saw afterwards. And I found that the best Latin manuscripts had vanities and not vain. But the truths I have drawn from this false reading are self-evident."