Sitra Achra (Aramaic for "the Other Side") is a Kabbalistic concept referring to the realm of impurity, evil, and spiritual obstruction, standing in opposition to the Sitra D’Kedushah (the Side of Holiness).
It is not an independent entity with its own divine will, but rather a necessary aspect of creation that conceals God’s presence, allowing for free will and the choice between good and evil.
The forces of the Sitra Achra are often described as Kelipot (shells or husks) that hide sparks of holiness. These include:
- Kelipat Nogah: A neutral shell that can be elevated and refined through righteous action.
- The Three Impure Kelipot: Shells that are entirely evil and resist elevation.
In practice, engaging in selfish acts or sins is believed to feed energy to the Sitra Achra, strengthening its influence, while Torah study and mitzvot are used to subdue these forces and reveal the hidden holiness within the material world.