Sayyid Ahmad was not pleased with Al-Mirghani's delay in Sudan and urged him to return so that he might receive good news and blessings from his teacher. Ibn Idris always addressed his student with gentle Sufi language, bestowing upon him titles with Sufi connotations. We find him addressing him as "Khalifat al-Rahman" (Successor of the Merciful) and "Markaz Da'irat al-'Irfan" (Center of the Circle of Gnosis), and "to the beloved and the delight of the eye, the ultimate goal of the Muhammadan saints, undoubtedly, a source of pride with the testimony of the Messenger of the Lord of the Worlds, Muhammad Uthman, who holds fast to the strongest bond in the station of faith and excellence," and "to the son and delight of the eye, and the apple of the eye, Muhammad Uthman, the chosen of the King, the Judge, whom the King, the Bestower, has chosen and made the essence of the chosen from the presence of the Generous Giver," and "to his son and the delight of his eye."

The correspondence between Al-Mirghani and Ibn Idris does not provide insight into the nature of the relationship between the Khatmiyya and the Idrisiyya. Their language was always vague and unclear. Al-Mirghani attributed his prolonged stay in Sudan and his delay in joining his teacher to economic reasons and the steady increase in the number of his followers and family members. Ibn Idris, in light of this, began to lose hope in the possibility of Muhammad Uthman's return. In the end, Muhammad Uthman returned to Mecca and stayed with his teacher after he moved to Sabya in 728 AH / 1813 AD, and remained there until Ibn Idris's death in 798 AH / 1881 AD.

After his teacher's death, Muhammad Uthman moved to Mecca and dedicated his efforts there to establishing his Khatmiyya order. He founded a number of zawiyas in Mecca, Medina, Jeddah, and Taif. He also sent his sons to preach in several regions. He sent his eldest son, Muhammad Sirr al-Khatm, to Yemen and Hadramaut, and appointed his son Muhammad al-Hasan as his representative in Sudan. Muhammad Uthman's success in Mecca aroused the envy of scholars, which compelled him to move to his region of Taif, where he remained until his death in May 1851 AD, corresponding to 1267 AH.