The "אש" that the bnai Yisrael saw during matan Torah and how it relates to tikkun leil Shavuot​​​​​​​. Shavuot 2018

(18) Now Mount Sinai was all in smoke, for the LORD had come down upon it in fire; the smoke rose like the smoke of a kiln, and the whole mountain trembled violently.

(2) You find that when the Holy One, blessed be He, gave the Torah, it was entirely of fire, as it is said: At His right hand was a fiery law unto them (Deut. 33:2). Our sages stated: The law was of fire, the parchment was of fire, its writings were of fire, the thread was of fire, as it is said: At His right hand was a fiery law. The face of the agent (Moses) became fiery, as is said: And they were afraid to come nigh him (Exod. 34:30). The angels who descended with it were of fire, as it is said: Who makes winds Thy messengers (Ps. 104:4). The mountain burned with fire (Deut. 4:11), and it was given within a fire consuming fire, as it is said: For the Lord thy God is a devouring fire (ibid. 4:24). And upon the earth He made thee to see His great fire (ibid., v. 36). The Divine Word also came forth from the midst of fire. When they beheld the lightning and the burning letters, the Holy One, blessed be He, said to them: Do not imagine that they have much power, and He began to recite the words I am the Lord thy God. Thou shalt have no other gods (Exod. 20:2).¹⁸The Ten Commandments. Cf. above, “In the Beginning,” n. Why were they described as gods? R. Yosé said: He did so in order not to give the people of the world the opportunity to say that they were not called by His name because if He had done so, it would have acknowledged that they had power. But they were called by His name, and yet have no power. When were they first called by His name? In the days of Enoch the son of Seth, as it is said: Then began man to call in the name of the Lord (Gen. 4:25). It was then that the Mediterranean Sea rose and inundated a third of the world, and the Holy One, blessed be He, said: Ye have done a new thing in calling yourself by My name, and so I will do something new and call Myself by My name. Therefore Scripture says: That calleth for the waters of the sea, and poureth them out upon the face of the earth, the Lord is His name (Amos 5:8).

The Gemara continues to praise the Sages. The Sages taught: Hillel the Elder had eighty students. Thirty of them were sufficiently worthy that the Divine Presence should rest upon them as it did upon Moses our teacher, and thirty of them were sufficiently worthy that the sun should stand still for them as it did for Joshua bin Nun, and twenty were on an intermediate level between the other two. The greatest of all the students was Yonatan ben Uzziel, and the youngest of them was Rabban Yoḥanan ben Zakkai. The Gemara relates: The Sages said about Rabban Yoḥanan ben Zakkai that he did not neglect TaNaCh; Mishna; Gemara; halakhot and aggadot; minutiae of the Torah and minutiae of the scribes; the hermeneutical principles of the Torah with regard to a fortiori inferences and verbal analogies; the calculation of the calendrical seasons; and numerology [gimmatreyaot]. In addition, he did not neglect esoteric matters, including the conversation of ministering angels; the conversation of demons, and the conversation of palm trees; parables of launderers, which are folk tales that can be used to explain the Torah; parables of foxes; and more generally, a great matter and a small matter. The Gemara elaborates: A great matter is referring to the secrets of the Design of the Divine Chariot, the conduct of the transcendent universe. A small matter is, for example, halakhot that were ultimately formulated in the framework of the disputes of Abaye and Rava. He did not neglect any of these disciplines so as to fulfill that which is stated: “That I may cause those that love me to inherit substance and that I may fill their treasuries” (Proverbs 8:21), as Rabban Yoḥanan was filled with the disciplines of Torah and wisdom. And if the youngest of them was so prolific, the greatest of them was all the more so prolific. The Gemara relates that the Sages said of Yonatan ben Uzziel, the greatest of Hillel’s students, that when he sat and was engaged in Torah study, the sanctity that he generated was so intense that any bird that flew over him was immediately incinerated.

And a similar thing occurred in the Medrash - concerning the incident with Rebbi Eliezer and Rebbi Yehoshua, when they were siting at a Se’udah, and a fire burned around them

so this happened to me: My father Abuyah was one of the notables of Jerusalem. On the day he came to circumcise me, he called all the notables in Jerusalem and sat them on one house; and Rabi Eliezer and Rabi Yehoshua in another house. After they ate and drunk, they sang, and clapped their hands and danced. Rabi Eliezer said to Rabi Yehoshua: Since they are occupied with what is theirs, let's occupy ourselves with what is ours. And they sat and occupied themselves with words of Torah. From Torah to Prophets. And from Prophets to Writings. And a fire came from heaven, and enveloped them. Abuyah said to them: My teachers,why have you came to burn my house down on me? They said to him: Chas veshalom! [Mercy and peace!] Rather, we were sitting and going over words of Torah, and from Torah to Prophets and from Prophets to Writings and the words were as joyful as when they were given on Sinai, and the fire was consuming them as they were consumed in Sinai, and the main thing of their being given in Sinai was solely [being given] on fire "And the mountain was on fire up to the heart of heaven" (Deut. 4:11) My father Abuya said to them: My teachers, if the power of Torah is such - if this child remains alive for me, I will dedicate him to Torah. Since his intention was not for Heaven, Torah did not remain alive in that man.

Ben Azzai was sitting and expounding, and fire was blazing around him. They [his disciples] came and told Rabbi Akiva, "Rabbi Ben Azzai is sitting and expounding, and fire is blazing around him." [Akiva] went to him and said, "I heard that you were sitting and expounding, and fire was blazing around you!" [Ben Azzai] replied, "Yes." [Akiva] said to him, "Perhaps you are engaged in the chambers of the Chariot [the secrets of Ezekiel's vision of the Chariot]?!" [Ben Azzai] replied, "No, I am sitting and stringing words of Torah, from Torah to the Prophets, and from Prophets to the Writings, and the words are as joyous as on the day they were given from Sinai, and as sweet (sonorous, fragrant) as the essence [ikar] of what was given. And the essence that was given [that day] on Sinai, were they not [originally] given in fire?!" and the mountain burned with fire (Deut. 4:11).

It happened once [on Pesach] that Rabbi Eliezer, Rabbi Yehoshua, Rabbi Elazar ben Azariah, Rabbi Akiva and Rabbi Tarfon were reclining in Bnei Brak and were telling the story of the exodus from Egypt that whole night, until their students came and said to them, "The time of [reciting] the morning Shema has arrived."

(1) ...It says in the Zohar that the original pious ones would be awake all the night working in Torah. And already most of those who learn do this. It's possible to give a reason for this according to its simple understanding, that Israel slept all the night, and the Holy One Blessed be He had to wake them, as the midrash says. Therefore, we need to fix this.