Zohar for All, Lech Lecha, Item 104: When the Ruach comes out of this world and enters the cave of Adam haRishon and the patriarchs, they give him there a letter as a sign, and he goes to the Garden of Eden. When he approaches, he meets the Cherubim there and that flaming sword which turns every way. If he is rewarded, they see the letter that is the sign, open the gate for him, and he enters. If not, they repel him outside.
From the spiritual point of view, a cave is a place where a person spends nine months of intrauterine development and then he lives there. In other words, a cave is an inanimate level of the habitat surrounding you. Initially, people lived in caves because the microclimate of a cave is the best for man. People knew how to choose a favorable place to live.
A cave has special properties; we are surrounded by the power of the Earth from all sides. We do not feel it because today we live in high-rise buildings, on floors above the ground. And according to Kabbalah, a person should not get too far away from it.
Of course, in our time, all this does not really matter anymore. We must use other forces.
When a person reaches the state of entering the cave of the forefathers where Abraham, Isaac, and Jacob are located, the three lines, he meets these basic root properties of his soul. Adam HaRishon, from whom these three spiritual properties come, is also there.
This cave is also called Machpelah, which means double cave, that is, the union of Bina and Malchut.
It is not just one cave. We can say that there is another one in it: Malchut and Bina in Malchut, or Bina and Malchut in Bina. That is, from the two properties of Bina and Malchut, four properties are obtained: Malchut, Bina, Bina in Malchut, and Malchut in Bina.
These are the four properties called by the name of the Creator: Yod-Hey-Vav-Hey or HaVaYaH. When a person discovers them in himself and shapes them correctly, he starts to perceive who created him and who directs him.
The four letters give him the first spiritual quality on which he ascends and becomes more and more similar to the Creator. Thus, he reaches the gates of the Garden of Eden. If he prepares correctly, then the angels, that is, forces, that should now reveal in him the state called the Garden of Eden act on him.
And if he is not prepared, then even despite the fact that he has received all the makings below: both the meeting of the Forefathers and the so-called letter (Igeret, Mikhtav), he does not reach the level of the Garden of Eden, he cannot reveal this property in himself, and he must go down and start his ascent again.
From KabTV’s “The Power of The Book of Zohar” #19