רדל”א

רַדְל”א is a deep term in the Kabbalah according to the Holy Ari, and is an acronym for:
“רֵישָׁא דְּלָא אִיתְיָדַע” 
—Reisha D’la Ityada, Aramaic for “The Head that is Not Known.”

This concept refers to the most hidden and unknowable aspect of the Divine ‘Mind’—the highest level of Keter (Crown). It is the point beyond all comprehension, even beyond what can be revealed in the spiritual worlds.

Where RADL”A Appears in the Structure of the Sefirot

In the structure of the Sefirot, the highest of all is Keter, which itself contains three inner layers or “heads” (reishin רישין):

1. Reisha D’lo Ityada (רַדְלָ”א) – The Head that is Not Known
2. Reisha D’Ayin – (רישא דאין) The Head of Nothingness
3. Reisha De’Arich – (רישא דאריך) The Long Face (beginning of Arich Anpin)

RADL”A is the innermost point of Keter, even beyond the grasp of the highest spiritual entities. It is associated with the primordial Will of the Creator, which is so pure and transcendent that it cannot be expressed or revealed—not even to the upper worlds such as Atzilut.

• Unknowable Origin of All Things: RADL”A represents the root of all existence, before thought, emotion, or form. It is the source of the Creator’s will that underlies all creation—but it remains hidden from every level of perception.

• Beyond Intellect: Even Chochmah, the highest level of Divine wisdom, does not reach RADL”A. It is called “the head that is not known” because no mental process or spiritual insight can penetrate it.

• Associated with Bitul (ביטול Self-Nullification): Connecting to RADLA is not about knowledge or grasp but about utter humility and bitul, the self-nullification that allows the soul to become aligned with the primordial Will of the Creator.
• The Zohar alludes to this level in its references to כתר עליון Keter Elyon, the supernal crown, which is described as not being grasped by any mind.
• The Holy Ari (Rabbi Isaac Luria) elaborates on RADL”A in his teachings on Atik Yomin and Arich Anpin, two aspects of the Keter in the world of Atzilut.
• RADL”A is said to reside in עתיק יומין Atik Yomin, the innermost and most transcendent aspect of the Will of the Creator.

Practical Reflection

While we cannot understand or perceive RADL”A, we are connected to it through faith (emunah) and Shabbat, which the Kabbalists associate with the Light of Keter. On Shabbat and during deep spiritual moments, one can receive a glimmer of the unknowable light, not through intellect, but through inner stillness and alignment with Hashem’s will.

RADL”A teaches us the power and holiness of what lies beyond understanding—an invitation to enter into wonder, humility, and deep trust in the Creator, Hashem.