The Gemara in Makkot, daf kaf-dalet amud aleph, is tremendous, tremendous. Fantastic Gemara. Listen to this. We know, Rabotai (my masters), we have 630 mitzvot (commandments). Taryag mitzvot (630 mitzvot). Really, there's a lot more under that. I mean, you pass that. But officially, there are 630 mitzvot.
The Gemara says that as the generations get closer and closer to Mashiach (Messiah), closer and closer to B'ezrat Hashem (with Hashem's help), when we're going to have Yerushalayim, Jerusalem, back with the Beit HaMikdash, we're going to have to put an emphasis on a certain type of mitzvot that are basically the main mitzvah you should put your full effort into. The Gemara in Makkot asks: What is the mitzvah we should put an emphasis on? And that's the ikar, that's the main mitzvah of the generations. The Gemara says like this: Ba Chavakuk, who was a navi, who was a prophet, he's one of the prophets. Vehe'emidan al achat: he took the whole Torah, he took all 630 mitzvot, and he said what it boils down to is one mitzvah. What is that one common denominator? What is that one mitzvah? A tzaddik, a righteous person, lives with trust in HaKadosh Baruch Hu.
The main mitzvah of the generations before Mashiach is going to come, the main, main mitzvah, is emunah, to really believe in Hashem. Now, if you notice, the Arizal says it doesn't say v'tzaddik be'emunato, you gotta have emunah. It says v'tzaddik be'emunato yichyeh, you gotta live with emunah. Sometimes a person can learn about emunah, can learn about God, learn about Hashem, how Hashem is so great and Hashem is so good, so much, but it's good to learn about it, but it always stays as a concept. It's almost like a subject called emunah. There's math, science, halakha (Jewish law), and there's something called emunah. Emunah is not a subject. Emunah is life. You need emunah. It's an emergency. You breathe, you breathe emunah.
Imagine, chas veshalom (God forbid), you have a guy who's suffocating on the floor. He needs air; he can't breathe. Imagine you tell that person, “Well, you know how air works. You know, really, you need air because air is with atoms and this.” They used to give him a whole science behind why you need air. First, give the guy air. Afterwards, you can tell him the whole background of how air works and how you need to breathe. That's what emunah is. It's important to talk about emunah. But step one: you need emunah. Right now, you need emunah. A person, you want to breathe life, you want to live, yichyeh, you want to be alive. You know what you need? You need to recognize that living with Hashem is life. It's an emergency to have emunah. That's what it says, v'tzaddik be'emunato yichyeh. A person that has emunah, that's a life person.