Dhūl-Nūn Abū l-Fayḍ Thawbān b. Ibrāhīm al-Miṣrī (Arabic: ذو النون المصري; d. Giza, in 245/859 or 248/862), often referred to as Dhūl-Nūn al-Miṣrī or Zūl-Nūn al-Miṣrī for short, was an early Egyptian Muslim mystic and ascetic of Nubian origin. Born in Upper Egypt in 796, Dhul-Nun is said to have made some study of the scholastic
disciplines of alchemy, medicine, and Greek philosophy in his early life, before coming under the mentorship of the mystic Saʿdūn of Cairo, who is described in traditional accounts of Dhul-Nun's life as both "his teacher and spiritual director." Celebrated for his legendary wisdom both in his own life and by later Islamic thinkers, Dhul-Nun has been venerated in traditional Sunni Islam as one of the greatest saints of the early era of Sufism.
In the book catching the thread mentions one of the incidents of Dhul-nun....."A story from the life of the ninth-century Sufi, Dhu-l-Nun, the Egyptian, illustrates this: I was wandering in the mountains when I observed a party of afflicted folk gathered together. “What befell you?” I asked. “There is a devotee living in a cell here,” they answered. “Once every year he comes out and breathes on these people and they are all healed. Then he returns to his cell, and does not emerge again until the following year.” I waited patiently until he came out. I beheld a man pale of cheek, wasted and with sunken eyes. The awe of him caused me to tremble. He looked on the multitude with compassion. Then he raised his eyes to heaven, and breathed several times over the afflicted ones. All were healed. As he was about to retire to his cell, I seized his skirt. “For the love of God,” I cried. “You have healed the outward sickness; pray heal the inward sickness.” “Dhu-l-Nun,” he said, gazing at me, “take your hand off me. The Friend is watching from the zenith of might and majesty. If He sees you clutching at another than He, He will abandon you to that person, and that person to you, and you will perish each at the other’s hand.” So saying, he withdrew into his cell.