Likutei Moharan 51:3/ליקוטי מוהר"ן נ״א:ג׳

13. Prior to the creation, when the creation was still in potential, so to speak, before He actualized it, it was entirely one, entirely true, entirely good, and entirely holy. Even the designation “pure” was not applicable. This is because purity applies only when impurity is also possible, as is written, “you will be purified of all your impurity” (Ezekiel 36:25). But when all is one, the aspect of “many intrigues”—which is the essence of evil and impurity, as explained above—has no place. For purity is a mean between holiness and impurity, through which impurity is rectified, as in, “you will be purified of all your impurity.”

2This is also the aspect of free will, which is a mean between two things. This does not appertain prior to the creation, when everything was one, because free will, which is the aspect of purity, is not applicable in oneness. But when the Holy One transformed the creation from potential to actual, then the aspect of purity immediately came into being. For when He transformed potential to actual, two entities existed: the aspect of oneness and the creation. Free will was then applicable, because [free will] is the aspect of purity, which is a mean between that which is one—to which [purity] stands in close proximity and has yet to reach “many intrigues,” which is evil and impurity—yet is also an indicator and a sign of the eventual devolvement into evil and impurity.

3Thus it is written in the Zohar (I, 48a), that the very hold which impurity has derives from the left side. For purity implies the existence of impurity, and is a sign of the eventual devolvement into impurity. Consequently, the possibility exists for purifying and elevating impurity to purity, for it itself devolved from purity, as in, “you will be purified of all your impurity.” It follows then that the very hold which impurity has derives from purity, which is free will, as explained above.

4Purity is the aspect of the left side, the aspect of Levi, corresponding to “You shall purify the Levites” (Numbers 8:5). And Levi is the aspect of the left side, as is known. Therefore, the very hold that impurity has derives from the left side, because the left is the aspect of purity from which impurity’s very hold derives, as explained above.

5All this—i.e., the aspect of the left side/purity/free will, from which comes the essential devolvement of impurity/evil/contrariety/falsehood—all this extends from after-the-creation, after the creation was transformed from potential to actual. For then there were, so to speak, two entities: oneness and the creation, as explained above. We see therefore that the very hold of falsehood, which is impurity, derives from a distancing from oneness—i.e., from the aspect of after-the-creation.