Final entrance into the transcendental realm of Knowledge and Truth would crown the various "states" of longing, fear, hope, love, intimacy, and trust which Allah had bestowed; the climatic / state would be experienced as an intoxicating and ineffable flash of divine illumination, bringing with it the certainty of divine love - the goal of the mystical theist in all lands.

But a few mystics were not theists. They substituted the Realm of Truth for Allah; and when the Buddhist influences penetrated Iraq, the Sufis there moved perilously close to atheism (as did some zindiq or free-thinking sufis), and emphasized self-annhilation as the entire goal.

These and others among the more extreme Sufis were recognized by the orthodox Moslems as heretics. ... p 721-2

Ghazzali, Muhji ed-din, "the Restorer (or Reviver) of Religion" 1058-1111 ce

"Ever since I was under twenty (now I am over fifty) ... I have not ceased to investigate every dogma and belief. No Batinite did I come across without desiring to investigate his esotericism; no Zaharite, without wishing to acquire the gist of his literalism; no philsopher (neo-Platonist), without wanting to learn the essence of his philosophy; no dialectical theologian, without striving to ascertain the object of his dialectics and theology; no Sufi, without coveting to probe the secret of his Sufism; no ascetic, without trying to delve into the origin of his asceticism; no atheistic zindiq, without groping for the causes of his bold atheism and zindiqism. Such was the unquenchable thirst of my soul for research and investigation from the early days of my youth, an instinct and a temperament implanted in me by God through no choice of mine. 45 p 725
45 Philip K. Hitti, History of the Arabs (Macmillan: NY 1937) p 431

Hallaj conceives the mystical union as union with the Creative Word (Kun , Be!),which in the Koran is appropriated to the birth of Jesus and the Resurrection,... p 722