Every Jew knows the custom: chassidim of old stayed awake all night on Shavuot, learning Torah until dawn. We call it Tikkun Leil Shavuot — "the repair of the night of Shavuot." But the word "tikkun" implies that something was broken. So the real question is: what exactly broke on the original night of Sinai?

The Mishnah Berurah writes: "It says in the Zohar that the early chassidim stayed awake all night and engaged in Torah." And he explains why: "Because Israel was sleeping all night, and the Holy One had to wake them up to receive the Torah — therefore we need to repair this." That is the standard answer: our ancestors slept on the night of Sinai, and we are now making the repair.

Imagine a child whose father says: "In a month and a half I'm going to buy you a brand-new bicycle." The child gets excited. Every day he counts: "One day to the bicycle... two days to the bicycle..." — until 49 days have passed.

Now the question: on the last night, the night before he gets the bicycle — can he sleep? Of course not. He doesn't even dream of a sandwich. That is human nature. Massive anticipation produces total insomnia.

The Torah states it explicitly: Moshe had to lead them out — meaning, someone had to bring them out. And what preceded that moment? "There were thunders and lightning and a heavy cloud upon the mountain and a very strong shofar blast, and all the people in the camp trembled." The thunder and lightning — what were they for?

A midrash says: they slept all night, "because the sleep of Shavuot is pleasant and the night is short." Shavuot falls at the end of Sivan — pleasant weather, neither hot nor cold, a short night. One could sleep easily.

But pay attention to another midrash: "Rabbi Yehuda said — not even a flea bit them." How is that possible? Six hundred thousand people in the desert, and not a single mosquito biting a single Jew to wake him up?

Why did God need to put Israel to sleep? What happened on that night that — if they had been awake — would have harmed them?

Our Sages teach: at the Giving of the Torah, the seven heavens opened — and Israel saw all the way to the Throne of Glory.

Now the question: how much Torah can one person learn in 7000 years? That is the volume of Torah — the magnitude of the download — that Israel received at Sinai in a single moment.

How can the soul of a Jew — a soul that had been lost for centuries in Egyptian slavery, that hadn't even opened a book of Tehilim — how can such a soul withstand a single instantaneous transfusion of that much spirituality without the heart and soul exploding on the spot?

And after the surgery — in the morning — the thunders, the lightning, the shofar. The greatest alarm clock in history. And all the people trembled. They woke up suddenly — and found themselves with the entire Torah inside them.

Our Sages teach in tractate Niddah: the fetus in the womb learns the entire Torah. A lamp burns above his head, and he sees from one end of the world to the other.

The answer is the secret: he doesn't forget — it gets hidden. The fetus cannot study the whole Torah once he's outside — this world doesn't allow it. But in the womb, above time and matter, he can. Then the potential is taken with him for life.

What remains for him to do is to retrieve, recall, remember. Every time you study Torah, you are not learning something new — you are unlocking a memory.

Now we understand: "tikkun" does not mean "fixing something broken." Think of matkin mazgan — "installing an air conditioner." The technician isn't repairing anything — he is installing something new. The root tikkun in Hebrew means installation, completion.

Even converts — their souls were present at Sinai. Every Jewish soul carries this immense potential. Your soul remembers.

On the night of Shavuot, a special divine illumination descends — capable of awakening this memory. It descends only on this night, in these hours. And if you are awake and studying, you connect to it.

That is the reason for the custom of Tikkun Leil Shavuot: not to "fix" — but to recall the experience of Sinai. So that everything that was injected under anesthesia — wakes up.

Some add: Tikkun Leil Shavuot is also the completion of all the Tikkun Chatzot of the entire year. All the midnight prayers — for the rebuilding of the Beit HaMikdash, for the redemption, for the dwelling of peace — on this night they reach their summit.

The foundation of all prayer is Tikkun Chatzot. And on the night of Shavuot, we complete those repairs. That is why Shavuot is the most spiritually charged night of the year.