The eighteenth day of the month of Elul, 12 days before Rosh HaShanah, is the day Rabbi Israel Baal Shem Tov was born, in 1698. 18/'Chai' Elul was also the day that he revealed the Chassidic movement on his 36th birthday in 1734. It presents a precious opportunity to inculcate into our lives his main teachings and his essence. To start, here are some of the principles that he made famous, found in the possession of a grandson of the Baal Shem Tov in Hamburg (copied from the holy handwriting of the Admor Moharash).
1. The entire Torah and the entire world contain nothing but the light of the Infinite One (blessed be He) concealed within them. All the verses that speak of this, such as "there is no other than He" and "I fill the heavens and the earth," are to be taken literally.
There is no act, word or thought in which the essence of divinity is not constricted and hiding. When you listen carefully to the inner voice within any physical sound...you will hear only the voice of G‑d…
And so when you look and see with your mind's eye, you will see the inner, life-force aspect of everything, not just its outer, superficial layer. You will see nothing but the divine power inside all things that is giving them life, being and existence at every moment.
And when you listen carefully to the inner voice within any physical sound that you hear, you will hear only the voice of G‑d as, at that moment, it is literally giving life and existence to the sound that you are hearing.
2. The "exile of G‑d's Presence" refers to the life-force and divine power that gives a person life and existence even at the moment that he is transgressing G‑d's will.
3. The evil inclination and lust are agents of G‑d. They carry out G‑d's will to mislead a person in order that he will overcome them.
From them, you can learn to be as mighty as they are. Just as they never slacken in their work but are trying to destroy you day and night (because a person always desires what his eyes see and what his ears hear), just as they are happy and delighted to carry out G‑d's will, it should be as clear to you that G‑d wants you to overcome them until you will conquer yourself and all your desires will be under your control - until you transform them to good.
This idea is alluded to in the verse, "We will take from it [from the flock] to serve G‑d," (Ex. 10:26) meaning that we will take a lesson from the evil inclination to act just as it acts to fulfill G‑d's will. And a word to the wise is sufficient.
4. Having no [divine] source, evil does not come down from heaven. Nevertheless, evil that exists has an inner power giving it life. And this [inner power] is total goodness. So if you look at the inner aspect of evil, you will only see the good in it.If you look at the inner aspect of evil, you will only see the good in it…
5. A person has to cling to the words that he speaks. Because each word contains a soul and divinity, when you cling to them, you are connected to divinity.
6. Everything that happens in the world, no matter how insignificant, comes from G‑d. And so do not concern yourself with whether or not what has occurred is in accordance with your will.
7. Neither thinking about the day of one's death nor the fear of punishment in hell will arouse a person's heart to serve G‑d. But yearning to cling to the source of life and goodness will do so. And neither fasting nor afflicting oneself will be of any help. But forgetting oneself out of the depth of one's yearning will do so.
8. Every person in his own right is [essentially] a complete spiritual Torah. If he goes in G‑d's path, that [Torah] is absorbed into his being, according to his level.
9. When a person prays for something that he needs, he should pray for the divine life-force hiding within that thing and giving it life, which is now suffering because of whatever it is lacking. And so one should ask G‑d to have pity on His life force that is hidden in that thing.
10. G‑d's Providence extends to all created beings, even to inanimate objects and plants. There is nothing that is not viewed from above in every detail. Everything was made with a particular intent. And a word to the wise is sufficient.
Additionally, Chai Elul starts the final count-down to Rosh Hashanah. It is taught that each of these last 12 days correspond to the 12 months of the ending year. On each consecutive day, we look into our "account books", checking to see if we served G‑d to our maximum during the corresponding month, and how we need to improve in the future.
[Translated by Yaacov-David Shulman from Kovetz Eliyahu, p. 14]