“And the glory of God dwelt on Mt. Sinai, and the cloud covered it six days, and He called unto Moses on the seventh day from the cloud. And the appearance of the glory of God was like a devouring fire at the summit of the mountain in the eyes of the Children of Israel. And Moses came in the midst of the cloud, and he ascended the mountain, and it was that Moses was in the mountain 40 days and 40 nights.” 
What is the importance of Moses’ 40-day stay on Sinai? In Deuteronomy, Moses tells the Jews that he fasted during these first 40 days on Sinai. (The omission here is of interest) Ibn Ezra states that Moses’ fast of 40 days and 40 nights is a “great, unprecedented wonder”. But we must learn whether this fasting was Moses’ idea, God’s command…or did it just happen? And what would be lost, had Moses not fasted? He would still have received the Torah, as it says “Ascend the mountain to Me and remain there and I will give you the Tablets of stone, and the Torah and the Mitzvah which I have written to teach them”. What difference would it make, had Moses received the Tablets, without fasting?
Let us review the order of Moses’ ascensions on Sinai. Moses first received and wrote the Torah, commencing with Genesis and concluding with his present-day, the event of Revelation on Sinai located in Parsha Yisro. This means that all of the Torah's historical content subsequent to Sinai (Parshas Yisro) was not yet given to Moses at Sinai. Moses then descends Sinai and informs the Jews of this Torah, which they accept. On the 7th of Sivan, Moses ascends Sinai for his first of three 40-day periods on the mountain, to receive the first Tablets. On his last day – 17th of Tammuz – Moses learns of the Jews sinning with the Golden Calf. He remains there on the mountain that last day, prays for the Jews not to be destroyed, and receives a favorable reply from God. But keep in mind that during these 40 days until the Jews sinned, Moses’ abstinence from food was not on account of any sin, since no sin was revealed to him until day 40. On this 40th day – the 17th of Tammuz – Moses descends, breaks the first set of Tablets, punishes the wicked Jews, and ascends to pray for the Jews. He prays for 40 days and night, until the 29th of Av: although God rescinded His initial decree to kill the nation, the Jews still bore the sin of the Golden Calf which Moses wished to remove during this second 40-day period. At God’s command to receive a replacement set of Tablets, Moses descends and quarries a new set of sapphire Tablets on which God will inscribe the original 10 Commandments. He then ascends for a final 40-day period dwelling on the mountain, and received complete atonement for the Jews on Yom Kippur, forty days after the 29th of Av. (Rashi)
When describing the actual events at Sinai in Exodus, the Torah omits any mention of Moses’ abstinence from food or drink, “…and it was that Moses was in the mountain 40 days and 40 nights.” Not a word of his abstinence. Why then does Moses tell the Jews about his fasting when he rebukes the Jews in Deuteronomy? The Torah is silent about his fast until this point:
“And in Horeb you angered God, and God was angered with you to destroy you. When I ascended the mountain, to receive the Tablets of stone, the Tablets of the Treaty which God forged with you; and I dwelled on the mountain 40 days and 40 nights; bread I did not eat, and water I did not drink.”
During those first 40 days to receive the first Tablets, the Jews had not yet sinned. Why then did Moses include this ascent in his rebuke? Additionally, why now does he mention his abstinence from food?
Moses continues his rebuke, “And I beseeched God like at first; 40 days and 40 nights, bread I did not eat and water I did not drink.” Here, Moses refers to his second ascent upon Sinai to obtain forgiveness for the Jews’ sin. But we wonder, why did Moses commence with the rebuke “And I beseeched God like at first”? What does Moses mean by the words “like at first”? We are surprised to read this, since we already proved that Moses first ascent was not for any sin of the Jews, but to receive the original Tablets at God’s command. This ascent predated the Golden Calf. So what is Moses’ equation between his second ascent to gain forgiveness, and his first ascent? We are forced to say that Moses’ abstinence during his first 40 days is somehow akin to his subsequent ascension and prayer for another 40 days after the Jews sinned, where he again did not require any nourishment. What is the equation?
What was Moses responding to with his second ascension on Sinai? The answer: the Golden Calf, the Jews’ sin of idolatry. What is this sin?
Idolatry is man’s attempt to gain goodness in his life, but does so through the misconception that animals, man, inanimate, or imaginary objects possess powers and can offer goodness. Humans are indeed dependent beings: we require food, clothing and shelter and have a myriad of insecurities. We sometimes become feeble, unsure that we can provide for ourselves, also in doubt about our future. Therefore, we succumb to hearsay regarding “powers” that can guarantee our needs. We create idols; seek out palm readers, even those as great as King Saul sought to resolve insecurities by inquiring of the dead. Unless we arm ourselves with truths, we will be no different. Parshas Shoftim clearly prohibits all such false practices, as Ibn Ezra says, “the Torah prohibits that which is false.”
This very need expressed in idolatry, is precisely what Moses emphasized, and desired to address. Moses teaches that we can obtain not only our needs, but so much more…but only with adherence to God. He tells the Jews that God “did one better” by removing any of his human needs. Idolatry attempts to secure the needs one has according to his natural disposition, that of an organism in need of food, clothing and shelter. And these, an idol cannot accomplish. In stark contrast, not only can God deliver those needs, but also, He can sustain man without needing to satisfy these natures…God can override nature. This is why Moses tells the Jews that he did not eat or drink, even during his first ascent, which had nothing to do with the Jews’ sin. During that first stay on Sinai, Moses attachment to God and His system procured such Divine Providence, that his normal needs were obviated. Revealing this great wonder to the Jews, Moses wished to awaken the sinful Jews to the exact foolishness of their sin. As an educator, Moses decided to unveil the Jews’ underlying notions that led to their sin: “You sought protection from gold which is inanimate, while God completely overrode my very needs. In this manner, Moses wished the Jews might realize their falsehoods, and abandon them. In this manner, they can truly repent. Informing the Jews that God removed his need to eat, Moses contrasted their idolatrous motivations, which never succeeded, to God’s manifest proof of His complete control over all. This should make an impression on those seeking security, that it could only come from God.
Earlier in Deuteronomy Moses states, “And He afflicted you and hungered you and fed you the Manna that you and your forefathers did not know, in order to make known that not on bread alone does man live, but on all that comes forth from God’s mouth does man live. Your clothing did not become worn from upon you, and your feet did not swell these forty years.” Again, Moses teaches the Jews how God sustained them with a miraculous food, how their clothing miraculously never wore, nor did they show physical symptoms normally met with those who traveled for so long.
Moses’ message is not that we should abandon natural law, for Moses himself would not do so. Moses’ entire life was spent educating the Jews about a land that would provide sustenance, for the very reason that we must live in accord with our natural needs. So what was Moses’ goal in mentioning all God’s miracles, and his endurance with no food for 40 days and nights?
Moses’ lesson is that while we witness natural law to be constant, we must have greater conviction in He who created and guides this law. If God says that Torah adherence will earn us all our needs, we must not abandon Torah because we feel this loss of work hours will lessen our income. We don’t know how God will assure our needs are met, and truthfully, we don’t need to know, nor can we know. God created this universe…do you know ‘how’ He did so? No man ever did. God’s knowledge and controls are unknowable, but His words are clear: He will provide, if we live the life He commands, for our own good. So if we are convinced that God exists, and that He does in fact control all, and that He promises to care for our needs if we follow Him, then other considerations must not take priority. Creating Golden Calves we assume will protect us, is an extreme illustration of the same falsehoods we harbor today: we work tirelessly, assuming everything we earn, is a result only of how much we work. God is not in our equations, just as God was not in the equation when the Jews created the Calf.
God addresses this insecurity in Malachi, where He says that we may test Him when giving our charity: “...and test Me please with this, says the Master of Hosts, (see) if I do not open up the storehouses of heaven, and empty out (for you) a blessing until you have more than enough”. God is guaranteeing that by giving tzedaka, we assure for ourselves financial security, and not an average income, but “until we have more than enough”. Our normal disposition is that when we part with money, we have less. But God teaches the opposite.
So what will you follow: human thinking based on natural law, or God, who created and controls those very laws?
Moses had no plan to abstain from natural law while on Mount Sinai. It happened that while there, engaged in prophecy and Torah study, God suspended natural law so that Moses endured for 40 days and 40 nights, awake, and not eating. Moses’ attachment to Torah earned him God’s providence. Our attachment to Torah will earn us providence as well.
 Exod. 24:16-18
 Exod. 24:18
 Exod. 24:12
 Rashi, Exod. 24:4,7. This is reasonable, since all subsequent events recorded in our Torah from Yisro through Deuteronomy had not yet transpired. And even if God had included these future events comprising the Jews’ future sins in this version of the Torah, free will would be affected, which violates God’s will.
 Exod. 32:14
 Deut. 9:11
 Deut. 9:18 states that Moses sought to remove the Jews’ “sin”, since he already obtained pardon from their destruction, as seen in Exodus 32:14.
 Deut. 9:8,9
 Deut. 9:18
 Samuel I, 28:7-19
 Lev. 19:31
 Deut. 8:3,4
 Malachi 3:10