"The word tajalli (pl. tajalliat) means theophany, theophan, self-disclosure or illumination. The Koran say: "And when Moses came to Our appointed time and his Lord spoke with him (kallamahu rabbuhu), he said, O my Lord, show me, that I may behold Thee! Said He. Thou shalt not see Me; but behold the mountain - if it stays fast in its place, then thou shalt see Me. And when his Lord revealed (tajalla rabbuhu) to the mountain He made it crumble to dust; and Moses fell down swooning" (7:143). The Prophet said, "God's veil is light. Were He to remove it, the glories of His face would burn away everything perceived by the sight of His creatures" (Ibn Majah, 13:293).
Tajalli is the process by which the Absolute, which is absolutely unknowable in itself, goes on manifesting itself in ever more concrete form. Since this self-manifestation of the Absolute cannot be actualized except through particular, determined form, the self-manifestation is nothing other than a self-determination or self-delimitation of the Absolute.
The tajalli is the radiation of Divine Light. So do not allow that God can be seen in Himself, that is, in His own Essence. God's Essence stands beyond every sort of delimitation, entification and relationship. There is "no thing" that could be witnessed by a something. However, God can be witnessed as He discloses Himself (tajalli). And He discloses Himself in every existent thing in the cosmos. When one's soul receives God's tajalli, it sees the whole cosmos as the Beak of the Real. In reality, it dawns on the heart unexpectedly provided one is prepared for it.
The tajalli is also called zil meaning shadow. The Koran says: "Do you not see how your Lord has lengthened His shadow (zilla)" (25:45)
There are three modes of tajalli:-
1. tajalli dhat : illumination of the divine essence
2. tajalli sifat ad-dhat : illumination of the divine attributes
3. tajalli hukm ad-dhat : illumination of the divine decree
There are two kinds of tajalli:
1. Tajalli-i Rahmani, and 2. Tajalli-i Ruhani
The first one is real, which blew the Mount Sinai to pieces. When one meditates, he perceives the first tajalli spiritually. The salik finds his I-ness annihilated. Thus, the desire for the sight of God becomes more and more intense. Several saliks have gone astray to perceive the second one and thought it the real one, it is evanescent