Maimonides

“ Similarly, in regard to man's conversation, he should speak only of those things that will be conducive to the true welfare of his soul and body, or that will tend to avert injury from them, whether his words concern themselves with science, or virtue, or praise of virtue or of a virtuous man, or with censure of vice or of a vicious person; for to express contempt for those who are loaded with vice, or to depict their deeds as contemptible—if done for the purpose of disparaging them in the eyes of other men who may avoid them, and not do as they do—is indeed a virtuous duty. ”

“ If there be found a man who has accomplished this—that is one who exerts all the faculties of his soul, and directs them towards the sole ideal of comprehending God, using all his powers of mind and body, be they great or small, for the attainment of that which leads directly or indirectly to virtue—I would place him in a rank not lower than that of the prophets. Such a man, before he does a single act or deed, considers and reflects whether or not it will bring him to that goal, and if it will, then, and then only, does he do it. ”

“ Thus, we have shown how utterly futile is the pretension to define His knowledge. All that we can comprehend is that just as we know that God exists so are we cognizant of the fact that He knows. If we are asked, "What is the nature of God's knowledge?", we answer that we do not know any more than we know the nature of His true existence. ”

“ The real duty of man is, that in adopting whatever measures he may for his well-being and the preservation of his existence in good health, he should do so with the object of maintaining a perfect condition of the instruments of the soul, which are the limbs of the body, so that his soul may be unhampered, and he may busy himself in acquiring the moral and mental virtues. ”

“ Suppose God had said that of those who were to be born in the future, some were to be transgressors and others observers of the Law, some pious and some wicked. Such would take place, but it would by no means follow from this divine decree that a certain individual would necessarily have to do evil, or that another pious individual would be forced to do good. On the contrary, every evil-doer would become such of his own free will; if he preferred to be a righteous man, it would be in his power, and nothing could prevent him from becoming such. ”

“ It is impossible for man to be born endowed by nature from his very birth with either virtue or vice, just as it is impossible that he should be born skilled by nature in any particular art. It is possible, however, that through natural causes he may from birth be so constituted as to have a predilection for a particular virtue or vice, so that he will more readily practise it than any other. ”

“ It is not necessary for us to know about God's wisdom so as to be able to ascertain why He inflicts precisely such punishment as He does and no other, just as little as we know why one species has a certain particular form and not another. It is sufficient for us to know the general principle, that God is righteous in all His ways, that He punishes the sinner according to his sin, and rewards the pious according to his righteousness. ”