It is written: “The whole Torah begins with a secret (Sod).” PARDES (acronym for the sequential attainment of spirituality) starts with “Sod” (secret) and ends with “Pshat” (knowledge, simple interpretation).
Presently, we don’t feel that we stand before the secret; it is all strictly hidden from us. Pshat means that everything becomes simple, clean, and open, which is the last step of attainment. When we begin attaining spirituality, we ascend from our world to the World of Assiya where we uncover Sod (secret); that is, we realize that everything is a mystery to us and it is all hidden. This is what we reveal in the World of Assiya.
When we ascend to the World of Yetzira, we uncover DRUSH (explanation), and if we reach the World of Beria, there we will discover REMEZ (hint). If we ascend to the World of Atzilut, we will reveal PSHAT (knowledge), and everything before us will open: the simple Upper Light that fills the entire reality.
From the 3rd part of the Daily Kabbalah Lesson 6/25/10, The Zohar