Saadiah in Emunoth ve-deoth iii. says: “Some men believe that we have no need of prophets, our reason being able to distinguish between good and evil. But if this were the case, God would not have sent messengers to us, because He does not do a thing that is purposeless. I considered the question thoroughly, and found that the mission of the prophets was necessary, not only for the promulgation of categorical commands, but also for that of rational precepts. Thus the duty of thanksgiving to God for His goodness is dictated by our own reason, but the Divine messengers had to fix the time and the form of thanksgiving. Again, adultery is rejected by our reason as a crime; but the Divine teaching determines the conditions of the bond that unites man and wife.... “As a test of the prophet’s truthfulness and trustworthiness a sign is given, which consists of an act implying a deviation from the ordinary laws of nature (comp. Exod. iii. and iv.). The Israelites are therefore frequently reminded of ‘the great wonders which their eyes saw’ (Deut. vii. 19). Those who believed after the sign was given were ‘the righteous,’ whilst those who did not believe ‘went astray.’ ... “The object of ‘the wonders’ was to produce belief in the prophecies; except for such a purpose as this, the regular course of Nature is not disturbed, so that man can make his plans and arrange his affairs on the basis of the continuance of the laws of Nature. The messengers sent by God were not angels, but men like ourselves, in order that the force of the sign may be more apparent; for, seeing that beings like ourselves perform things which we cannot perform, we conclude that a higher Being has endowed them with extraordinary power for a special purpose. If, however, angels had been chosen for the task of prophets, we should not have considered their performance as signs; but, not knowing the nature of angels, we should have thought that such acts were within the regular and natural powers of angels. Prophets, like other human beings, cannot dispense with the regular functions of the organs of their body; they are subject to the different conditions of health; to poverty, ill-treatment on the part of their fellow-men, and to ignorance about future events, except those communicated to them by Divine inspiration.—I found it necessary to state this here, because there are people who believe that the prophet does not die like ordinary people; others deny him the sensation of hunger and thirst; others again think that he does not suffer from violence and wrong directed against him, and some even believe that nothing is hidden from him. These ‘do not know the thoughts of the Lord, and do not understand His counsel.’ “It is, further, my conviction that the prophets were satisfied, by some extraordinary supernatural phenomena, that they were addressed by the Almighty. (Comp. Exod. xxxiii. 9 and Ps. xcix. 7: ‘In a pillar of cloud he speaketh to them.’)