When was the Torah actually given?
ותתן לנו יקוק אלקנו באהבה מועדים לשמחה חגים וזמנים לששון, את יום חג השבעות הזה זמן מתן תורתנו
Hashem our G-d, with love give us festivals of happiness, holidays and times of joy, this holiday of Shavuos, the time of the giving of our Torah
In our calendar Shavuos always falls out on the sixth day of Sivan. Something not mentioned explicitly in the Torah is the event that Shavuos commemorates. As noted in our prayers, Shavuos commemorates the giving of the Torah at Mount Sinai. This is why we read the Ten Commandments Shavuos morning. There’s actually a disagreement in the gemarra what day the Torah was given. The Rabbis say that the Torah was given on the sixth of Sivan, whereas Rabbi Yossi says that it was given on the seventh of Sivan. What is the basis for their argument?
The gemarra spells out the timeline of the whole episode. There are a few facts that everyone agrees to. First, everyone agrees that the Jews arrived at the wilderness of Sinai on Rosh Chodesh Sivan, the first day of the month. Second, everyone agrees that the Torah was given on Shabbos. They disagree about what day of the week Rosh Chodesh fell on that year. Rabbi Yossi believes that it fell on Sunday. On that day nothing happened, giving the people time to rest from their journeys. On Monday they were told they would be a Kingdom of Priests and a Holy Nation. On Tuesday they were commanded to distance themselves from the mountain in advance of the Divine Revelation. On Wednesday they were told to maintain a state of purity in preparation for the prophecy. Even though Hashem told them to prepare for only two days, Moshe on his own added an extra day. This gave them three days of preparation, until the giving of the Torah on Shabbos, on the seventh of the month. The Rabbis believe it was the same order of events, except that Rosh Chodesh was on Monday and they had only two days of preparation, so that the giving of the Torah on Shabbos was on the sixth of the month.
A contradiction that is pointed out is that we actually rule like Rabbi Yossi, that there were three days of preparation before the revelation at Sinai. This means that the Torah was really given on the seventh of Sivan, not the sixth. How then on Shavuos, the sixth day of Sivan, can we say that it’s the day of the “giving of our Torah”? It wasn’t given until the next day! The Beis HaLevi gives a fascinating answer. It’s based off of a gemarra further in the story of the giving of the Torah. The gemarra describes what happened when Moshe went up to heaven to bring down the Torah to the Jewish people. The angels were protesting to Hashem that the Torah should remain in heaven where it belongs. Hashem asked Moshe to respond to them. Moshe asked the angels how the Torah could be relevant to them. The first of the Ten Commandments is “I am Hashem your G-d who took you out of Egypt”, were the angels slaves in Egypt and were freed? The second commandment is “Don’t have any other G-ds”, are the angels tempted by such ideas? “Honor your father and mother”, do angels have parents? And so on. The angels withdrew their protests and acknowledged that Hashem was correct in giving the Torah to the Jews.
This story is very strange. Why did the angels want the Torah? Moshe had very good points; it had no relevance to them. The Beis HaLevi explains that the angels didn’t want the Written Torah. They wanted the Oral Torah. They wanted the power to elucidate and expand on the laws of the Torah. The Jews were given the Written Torah as well as the power to determine its final interpretation. This is what the angels desired. This explanation answers the contradiction regarding Shavuos. We rule the Torah was given on the seventh of Sivan, how can we say in our prayers that the sixth is the time of the giving of our Torah? The answer is that there really was a gift of the Torah on the sixth. What was it? This very power of authority that the angels craved. Hashem didn’t need to heed Moshe’s decision to have an extra day of preparation, and could have given the Torah on the sixth of Sivan, as originally commanded. By not coming until the seventh, He was showing that He had given the power of halachic ruling to man. This is the gift that we are mentioning in our prayers. This is why we say “the giving of our Torah” and not simply the giving of the Torah; it’s ours to determine.
 Based on a shiur given by Rabbi Elimelech Reznick on parshas Bamidbar 5773
 From the Festival Shemoneh Esrei and evening Kiddush prayers
 As opposed to when the Jewish calendar wasn’t fixed, and the start of the months depended on the testimony of two witnesses who saw the New Moon. See Rosh Hashanah 1:1-3:1
 Megillah 31a
 Shabbos 86b
 ibid 86b – 87a
 It says in Exodus 19:1 ביום הזה באו מדבר סיני, and it says ibid 12:2 החודש הזה לכם ראש חדשים, just like there it’s Rosh Chodesh so too here
 It says in the Ten Commandments (ibid 20:8) זכור את יום השבת לקדשו and it says in ibid 13:3 ויאמר משה אל העם זכור את היום הזה, just like there it’s referring to remembering the fact that they left Egypt on that very day, so too here the Ten commandments were given on that very day, meaning Shabbos
 Exodus 19:6
 Rashi to Shabbos 87a explains that Moshe only ever went up Mount Sinai in the morning, so when he came down to instruct the people he couldn’t go back up for more instructions until the next day
 Exodus 19:12
 By temporarily separating from their spouses
 ibid verse 15
 Exodus 19:11 says to be prepared for the third day, implying a need for only two days of preparation
 As we’ll see, the gemarra loc. cit. points out that Hashem actually approved of this act, considering He didn’t descend His presence on the mountain until Shabbos, after three days of preparation
 Magen Avraham 494:1
 The underlying disagreement between the Rabbis and Rabbi Yossi is how long must a couple temporarily separate before spiritual purification can commence. Rabbi Yossi rules that there needs to be six twelve-hour periods, meaning three days, which is actually the halacha found in Shulchan Aruch Yoreh Deah 196:11
 The Magen Avraham loc. cit. suggests a simple answer: we really rule like the Rambam in Hilchos Avos HaTumah 5:11 (see Kesef Mishnah ad. loc.) who says there’s only a need for three twelve-hour periods, which fits with the opinion of the Rabbis, and the ruling in Yoreh Deah is just a stringency. Therefore the custom in our prayers is based off of the opinion of the Rambam
 Exodus Chapter 19 s.v. להבין
 Shabbos 88b – 89a
 Exodus 20:2
 ibid verse 3
 ibid verse 12
 See Teshuvas Radvaz III § 643 (אלף ס”ח) for another interesting answer to this question
 See the episode in Bava Metzia 59b about the concept of לא בשמים היא, the Torah is not in Heaven
 The Beis HaLevi distinguishes between מתן תורה on the sixth and קבלת התורה on the seventh