The third class of evils comprise those which everyone causes to himself by his own action. This is the largest class, and is far more numerous than the second class. It is especially of these evils that all men complain, - only few men are found that do not sin against themselves by this kind of evil. ...This class of evil originates in man's vices, such as excessive desire for eating, drinking, and love; indulgence in these things in undue measure, or in improper manner, or partaking of bad food. This course brings diseases and afflictions upon the body and soul alike.
MaimonidesWHEN reading my present treatise, bear in mind that by "faith" we do not understand merely that which is uttered with the lips, but also that which is apprehended by the soul, the conviction that the object [of belief] is exactly as it is apprehended. If, as regards real or supposed truths, you content yourself with giving utterance to them in words, without apprehending them or believing in them, especially if you do not seek real truth, you have a very easy task as, in fact, you will find many ignorant people professing articles of faith without connecting any idea with them.
MaimonidesFurther, there are things of which the mind understands one part, but remains ignorant of the other; and when man is able to comprehend certain things, it does not follow that he must be able to comprehend everything.
MaimonidesTruth does not become more true by virtue of the fact that the entire world agrees with it, nor less so even if the whole world disagrees with it.
Maimonides