The more we desire for that which is superfluous, the more we meet with difficulties; our strength and possessions are spent in unnecessary things, a… - Moshe ben Maimon

The most evident of the wonders described in the book On the Use of the Limbs [by Galen]... is clearly perceived by all who examine them with a sharp eye. In a similar manner did God provide for each individual animal of the class of mammalia. When such an animal is born it is extremely tender, and cannot be fed with dry food. Therefore breasts were provided which yield milk, and the young can be fed with moist food which corresponds to the condition of the limbs of the animal, until the latter have gradually become dry and hard. Many precepts in our Law are the result of a similar course adopted by the same Supreme Being. It is, namely, impossible to go suddenly from one extreme to the other; it is therefore according to the nature of man impossible for him suddenly to discontinue everything to which he has been accustomed.

Even when a person suffers pain in consequence of a thorn having entered into his hand, although it is at once drawn out, it is a punishment that has been inflicted on him, and the least pleasure he enjoys is a reward; all this is meted out by strict justice; as is said in the Scripture, "all His ways are judgement" (Deut. xxxii. 4); we are only ignorant of the working of that judgement.

The prophet [ Isaiah ]... points out what will be the cause of this change; for he says that hatred, quarrel, and fighting will come to an end, because men will have a true knowledge of God. "They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the Lord, as the waters which cover the sea" (Isa. xi. ver. 9) Note it.