Question: The Book of Zohar is a commentary on the Torah. Why did it have to be written?
Answer: Circumstances changed.
There were stages when groups of Kabbalists who were in a state of attainment, that is, a gradual rise from the beginning of the creation of egoism to its relatively complete development, as during the Second Temple, fell. The Book of Zohar was written in the second century AD in a state when a fall had already occurred. There were no groups, no nations; there was nothing called holiness, meaning a sense of at least relative unity. Everything was destroyed, crushed, split. Therefore, a technique was needed to crown this dark period of suffering, called the exile, which should end in correction.
The Book of Zohar is intended for the period separated from its writing to our time by a two-thousand-year exile so that, starting from our time onward, we begin to implement what is written in it, meaning to correct ourselves.
In our generation, we have been awarded The Sulam Commentary on The Book of Zohar. Therefore, we can reveal Kabbalah and begin to understand what the great Kabbalists Rabbi Shimon and his students said two thousand years ago.
Question: Are you saying that without the commentary written by the last Kabbalist of the 20th century, Baal HaSulam (Yehuda Ashlag) it is impossible to understand the Zohar?
Answer: Impossible. Therefore, it appeared.
From KabTV’s “Fundamentals of Kabbalah,” 12/18/18