על החוקים לפרטיהם, ספר ב ל״בOn the Special Laws, Book II 32

א׳
1[193] The next feast held after the “Trumpets” is the Fast.  Perhaps some of the perversely minded who are not ashamed to censure things excellent will say, What sort of a feast is this in which there are no gatherings to eat and drink, no company of entertainers or entertained, no copious supply of strong drink nor tables sumptuously furnished, nor a generous display of all the accompaniments of a public banquet, nor again the merriment and revelry with frolic and drollery, nor dancing to the sound of flute and harp and timbrels and cymbals, and the other instruments of the debilitated and invertebrate kind of music which through the channel of the ears awaken the unruly lusts?
ב׳
2[194] For it is in these and through these that men, in their ignorance of what true merriment is, consider that the merriment of a feast is to be found. This the clear-seeing eyes of Moses the ever wise discerned and therefore he called the fast a feast, the greatest of the feasts, in his native tongue a Sabbath of Sabbaths,  or as the Greeks would say, a seven of sevens, a holier than the holy. He gave it this name for many reasons.
ג׳
3[195] First, because of the self-restraint which it entails; always and everywhere indeed he exhorted them to shew this in all the affairs of life, in controlling the tongue and the belly and the organs below the belly, but on this occasion especially he bids them do honour to it by dedicating thereto a particular day. To one who has learnt to disregard food and drink which are absolutely necessary, are there any among the superfluities of life which he can fail to despise, things which exist to promote not so much preservation and permanence of life as pleasure with all its powers of mischief?
ד׳
4[196] Secondly, because the holy-day is entirely devoted to prayers and supplications, and men from morn to eve employ their leisure in nothing else but offering petitions of humble entreaty in which they seek earnestly to propitiate God and ask for remission of their sins, voluntary and involuntary, and entertain bright hopes looking not to their own merits but to the gracious nature of Him Who sets pardon before chastisement.
ה׳
5[197] Thirdly, because of the time at which the celebration of the fast occurs, namely, that when all the annual fruits of the earth have been gathered in. To eat and drink of these without delay would, he held, shew gluttony, but to fast and refrain from taking them as food shews the perfect piety which teaches the mind not to put trust in what stands ready prepared before us as though it were the source of health and life. For often its presence proves injurious and its absence beneficial.
ו׳
6[198] Those who abstain from food and drink after the ingathering of the fruits cry aloud to us with their souls, and though their voices utter no sound, their language could hardly be plainer. They say, “We have gladly received and are storing the boons of nature, yet we do not ascribe our preservation to any corruptible thing, but to God the Parent and Father and Saviour of the world and all that is therein, Who has the power and the right  to nourish and sustain us by means of these or without these.
ז׳
7[199] See, for example, how the many thousands of our forefathers as they traversed the trackless and all-barren desert, were for forty years, the life of a generation, nourished by Him as in a land of richest and most fertile soil; how He opened fountains unknown before to give them abundance of drink for their use; how He rained food from heaven, neither more nor less than what sufficed for each day, that they might consume what they needed without hoarding, nor barter for the prospect of soulless stores  their hopes of His goodness, but taking little thought of the bounties received rather reverence and worship the bountiful Giver and honour Him with the hymns and benedictions that are His due.”
ח׳
8[200] By order of the law the fast is held on the tenth day. Why on the tenth? As has been shewn in our detailed discussion of that number,  it is called by the learned the all-perfect, and embraces all the progressions, arithmetical, harmonic and geometrical, and further the harmonies, the fourth, the fifth, the octave and the double octave, representing respectively the ratios 4:3, 3:2, 2:1 and 4:1, and it also contains the ratio of 9:8, so that it sums up fully and perfectly the leading truths of musical science, and for this reason it has received its name of the all-perfect.
ט׳
9[201] In ordaining that this privation of food and drink should be based on the full and perfect number 10, he intended to prescribe the best possible form of nourishment for the best part of us. He did not wish anyone to suppose that as their instructor in the mysteries he was advocating starvation, the most intolerable of sufferings, but only a brief stoppage in the influx which passes into the receptacles of the body.
י׳
10[202] For this would ensure that the stream from the fountain of reason should flow pure and crystal-clear with smooth course into the soul, because the constantly repeated administrations of food which submerge the body sweep the reason away as well, whereas if they are checked, that same reason stoutly fortified can in pursuit of all that is worth seeing and hearing make its way without stumbling as upon a dry firm causeway.
י״א
11[203] Besides, it was meet and right when everything has shewn abundance as they would have it, and they enjoy a full and perfect measure of goodness, that amid this prosperity and lavish supply of boons, they should by abstaining from food and drink remind themselves of what it is to want, and offer prayers and supplications, on the one hand to ask that they may never really experience the lack of necessities, on the other to express their thankfulness because in such wealth of blessings they remember the ills they have been spared. Enough on this matter.