The Book of Zohar, Chapter “Truma (Donation),” Item 422: But I am perplexed about the sages of the generation—how they let even one moment be without standing before Rabbi Shimon and studying Torah while Rabbi Shimon is in the world. But in this generation the wisdom will not be forgotten from the world. Woe unto the world when he departs, the sages grow fewer, and the wisdom is forgotten from the world.
This is not a reference to history. The generation of Rabbi Shimon is an exalted spiritual degree that one can connect to and consequently can receive from this great degree called “Rabbi Shimon.” “Rabbi Shimon” is not the name of an individual, but that of the source of Light of a particular degree (Arich Anpin of the world of Atzilut).
Therefore, one must take care not to lose one’s internal, constant aspiration to be connected to The Zohar—the very Light that exists at the degree called “Rabbi Shimon.” Then, to the extent of one’s approaching or distancing from this degree, one can gauge one’s advancement in or distancing from the spiritual work.
From the 2nd part of the Daily Kabbalah Lesson 7/7/2011, The Zohar