For the mind, shut in by earthly organs, and hindered by a corrupt  body, of itself can neither comprehend nor receive the truth, unless it is taught from another source.  And if it had this power in the greatest degree, yet it would be unable to attain to the highest virtue, and to resist all vices, the materials of which are contained in our bodily  organs. Hence it comes to pass, that an earthly teacher cannot be perfect. But a teacher from heaven, to whom His divine nature gives knowledge, and His immortality gives virtue, must of necessity in His teaching also, as in other things, be perfect and complete. But this cannot by any means happen, unless He should take to Himself a mortal body. And the reason why it cannot happen is manifest. For if He should come to men as God, not to mention that mortal eyes cannot look upon and endure the glory of His majesty in His own person, assuredly God will not be able to teach virtue; for, inasmuch as He is without a body, He will not practice the things which He will teach, and through this His teaching will not be perfect. Otherwise, if it is the greatest virtue patiently to endure pain for the sake of righteousness and duty, if it is virtue not to fear death itself when threatened, and when inflicted to undergo it with fortitude; it follows that the perfect teacher ought both to teach these things by precept, and to confirm them by practice. For he who gives precepts for the life, ought to remove every method  of excuse, that he may impose upon men the necessity of obedience, not by any constraint, but by a sense of shame, and yet may leave them liberty, that a reward may be appointed for those who obey, because it was in their power not to obey if they so wished; and a punishment for those who do not obey, because it was in their power to obey if they so wished. How then can excuse be removed, unless the teacher should practice what he teaches, and as it were go before  and hold out his hand to one who is about to follow? But how can one practice what he teaches, unless he is like him whom he teaches? For if he be subject to no passion, a man may thus answer him who is the teacher: It is my wish not to sin, but I am overpowered; for I am clothed with frail and weak flesh: it is this which covets, which is angry, which fears pain and death. And thus I am led on against my will;  and I sin, not because it is my wish, but because I am compelled. I myself perceive that I sin; but the necessity imposed by my frailty, which I am unable to resist, impels me. What will that teacher of righteousness say in reply to these things? How will he refute and convict a man who shall allege the frailty of the flesh as an excuse for his faults, unless he himself also shall be clothed with flesh, so that he may show that even the flesh is capable of virtue? For obstinacy cannot be refuted except by example. For the things which you teach cannot have any weight unless you shall be the first to practice them; because the nature of men is inclined to faults, and wishes to sin not only with indulgence, but also with a reasonable plea.  It is befitting that a master and teacher of virtue should most closely resemble man, that by overpowering sin he may teach man that sin may be overpowered by him. But if he is immortal, he can by no means propose an example to man. For there will stand forth some one persevering in his opinion, and will say: You indeed do not sin, because you are free from this body; you do not covet, because nothing is needed by an immortal; but I have need of many things for the support of this life. You do not fear death, because it can have no power against you. You despise pain, because you can suffer no violence. But I, a mortal, fear both, because they bring upon me the severest tortures, which the weakness of the flesh cannot endure. A teacher of virtue therefore ought to have taken away this excuse from men, that no one may ascribe it to necessity that he sins, rather than to his own fault. Therefore, that a teacher may be perfect, no objection ought to be brought forward by him who is to be taught, so that if he should happen to say, You enjoin impossibilities; the teacher may answer, See, I myself do them. But I am clothed with flesh, and it is the property of flesh to sin.  I too bear the same flesh, and yet sin does not bear rule in me. It is difficult for me to despise riches, because otherwise I am unable to live in this body. See, I too have a body, and yet I contend against every desire. I am not able to bear pain or death for righteousness, because I am frail. See, pain and death have power over me also; and I overcome those very things which you fear, that I may make you victorious over pain and death. I go before you through those things which you allege that it is impossible to endure: if you are not able to follow me giving directions, follow me going before you. In this way all excuse is taken away, and you must confess that man is unjust through his own fault, since he does not follow a teacher of virtue, who is at the same time a guide. You see, therefore, how much more perfect is a teacher who is mortal, because he is able to be a guide to one who is mortal, than one who is immortal, for he is unable to teach patient endurance who is not subject to passions. Nor, however, does this extend so far that I prefer man to God; but to show that man cannot be a perfect teacher unless he is also God, that he may by his heavenly authority impose upon men the necessity of obedience; nor God, unless he is clothed with a mortal body, that by carrying out his precepts to their completion  in actions, he may bind others by the necessity of obedience. It plainly therefore appears, that he who is a guide of life and teacher of righteousness must have a body, and that his teaching cannot otherwise be full and perfect, unless it has a root and foundation, and remains firm and fixed among men; and that he himself must undergo weakness of flesh and body, and display in himself  the virtue of which he is a teacher, that he may teach it at the same time both by words and deeds. Also, he must be subject to death and all sufferings, since the duties of virtue are occupied with the enduring of suffering, and the undergoing death; all which, as I have said, a perfect teacher ought to endure, that he may teach the possibility of their being endured.
 Propria.  Tabe corporis.  Thus our Lord tells us that flesh and blood cannot reveal to us mysteries.  Visceribus.  Omnium excusationum vias. [Here is the defect of Cicero's philosophy. See William Wilberforce, Practical Christianity, p. 25, ed. London, 1815.]  Prævius.  Thus St. Paul complains, Romans 7:15: "What I would, that do I not; but what I hate, that do I;" and ver. 21, "I find then a law that when I would do good, evil is present with me." But (viii. 3) he says, "What the law could not do, in that it was weak through the flesh, God, sending His own Son in the likeness of sinful flesh, condemned sin in the flesh."  Cum ratione.  This is urged as an excuse by him to whom the precept is addressed. In this and the following sentences there is a dialogue between the teacher and the taught.  Præcepta sua factis adimplendo.  Virtutem in se recipere.
 Tabe corporis.
 Thus our Lord tells us that flesh and blood cannot reveal to us mysteries.
 Omnium excusationum vias. [Here is the defect of Cicero's philosophy. See William Wilberforce, Practical Christianity, p. 25, ed. London, 1815.]
 Thus St. Paul complains, Romans 7:15: "What I would, that do I not; but what I hate, that do I;" and ver. 21, "I find then a law that when I would do good, evil is present with me." But (viii. 3) he says, "What the law could not do, in that it was weak through the flesh, God, sending His own Son in the likeness of sinful flesh, condemned sin in the flesh."
 Cum ratione.
 This is urged as an excuse by him to whom the precept is addressed. In this and the following sentences there is a dialogue between the teacher and the taught.
 Præcepta sua factis adimplendo.
 Virtutem in se recipere.