Milchigs on Shavuos

(1) The fiftieth day of the count of the Omer is the holiday of Shavuot...

(3) It is prohibited to fast immediately after the holiday of Shavuot. Ramah: And we do not say Tachanun from the beginning of Rosh Chodesh Sivan until the 8th day, which is after the post-holiday day (Hagahot Maimoni, Hil' Tefillah Umnagim). We have the custom to spread out plants on Shavuot in the synagogue and in houses, as a memory for the happiness of the receiving of the Torah. We have a custom everywhere to eat dairy food on the first day of Shavuot. And it seems to me that the reason is: It is like the two foods that are taken on the evening of Pesach, a reminder of the Korban Pesach and a reminder of the Korban Chagiga, so too we eat a dairy food followed by a meat food, and we bring with them two loaves on the table in place of the Mizbeach, and thus there will be a reminder of the two loaves that were brought on "The day of the Bikkurim."

(16) you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to Hashem.

(26) On the day of the first fruits, your Feast of Weeks, when you bring an offering of new grain to Hashem, you shall observe a sacred occasion: you shall not work at your occupations.

(6) There are many reasons for eating dairy, I will copy the reason written in the Zohar: the previous seven weeks were in parrallel to the seven clean days a woman counts before immersing in the mikvah, we know that blood becomes milk, this is parallel to the movement from judgement to mercy, and the practice of our fathers is in our hands to fulfill. However, it is important to be careful not to violate any prohibitions (see Yoreh Deah 89)...

The menstrual blood is decomposed and turns into milk.

Dairy foods - See Magen Avraham and I also heard in the name of a Gadol who said a correct reason for this: that when Bnei Yisrael stood at Har Sinai and accepted the Torah(When the 10 commandments were revealed, and through this all the parts of the Torah were also revealed to them, like that Rav Sadya Gaon writes, that the 10 commandments sustain the whole Torah) and they went down from the mountain to their homes they found nothing to eat immediately except for dairy foods because for meat they would need much preparation to slaughter with a checked knife like Hashem commanded... And to clean out the strings of forbidden fats and blood, and to rinse and salt(the meat). Also to cook in new vessels because their previous vessels had been used to cook meat (that they now discovered was actually trief) had been used in the last 24 hrs (which is what is forbidden Biblically) so their old vessels were forbidden to them, therefore they choose on account of the time to eat dairy foods and we do this as a commemoration of this.

The Kol Bo writes that it is a custom (on Shavuos) to eat honey and milk for the Torah is compared to these two foods.

(16) A mountain of God is the mountain of Bashan; A mountain of peaks (Givunim) is the mountain of Bashan.

The Gemara asks: And from where do we derive that the milk of a kosher animal is in fact permitted?...

And if you wish, say instead that proof may be brought from here: The Torah praises Eretz Yisrael as: “A land flowing with milk and honey” (Exodus 3:17), and if milk was not permitted, would the verse praise the land to us with an item that is not suitable for consumption?

When Moshe ascended on High to receive the Torah The Angels wished to hurt him (to prevent him from taking the Torah). So Hashem miraculously changed his face to appear like Avraham Avinu. Hashem said to them; "Are you not embarrassed from (Avraham), for you went and ate in his house...

(1) ויקח חמאה וחלב, “he took curd and milk, etc.” this teaches that he fed them both milky and meaty dishes. When G–d was ready to give the Torah to the Israelites, the angels are reported as having said to Him (Psalms 8,2): תנה הודך על שמים, “You have covered the heavens with Your glory” [This is perceived as the angels demanding that the Torah remain in the celestial regions of the universe. Ed.] G–d replied to them: “in My Torah it is written that milky and meaty dishes not be consumed at the same meal (Exodus 23,19), yet when you descended to earth you partook of such a mixture at Avraham’s table. (The inference is clear, i.e. “the laws of the Torah do not apply to you.”) As soon as the angels heard this they withdrew their objections to the Torah being given to people on earth. This is the deeper meaning of Exodus 34,27: כי על פי הדברים האלה כרתי אתך ברית ואת ישראל, “for in accordance with these words I have made a covenant with you and with Israel.” What do “these words” refer to? They refer to the verse prior to this where eating meaty and milky dishes at the same time has been prohibited. Nonetheless, this metaphorical explanation appears to contradict another metaphorical interpretation (Midrash) in which we have been taught that Avraham personally observed not only all the Biblical laws of the Torah, but even the “fences” surrounding them to protect us against violating the prohibition itself. The particular example quoted there for such a “fence” is interestingly the subject of eyruv tavshilin, certain preparations of food when the holiday occurs immediately before the Sabbath. But that is not the only way of explaining the Midrash. The word: eyruv, actually means “mixture,” so that the Midrash may have referred to a mixture of meaty and milky courses of the same meal, so that there is no contradiction at all. Seeing that Avraham is reported as first having served milky dishes, and the meat subsequently, it is reasonable to assume that he wished to give his guests something to eat before freshly slaughtered animals, that had to have their blood removed could be cooked or roasted on the spit. The interval would have sufficed not to violate the laws of mixing milk and meat. [If people ate their main meal during the fourth hour after sunrise, seeing that these men (angels) did not arrive at Sodom until evening, there would have been plenty of time for their eating both. Ed.]

(26) The choice first fruits of your soil you shall bring to the house of Hashem your God. You shall not boil a kid in its mother’s milk.

(27) And Hashem said to Moshe: Write down these commandments, for in accordance with these commandments I make a covenant with you and with Israel.