It is not known when Saʿd al-Dīn became a disciple of Najm al-Dīn Kubrā, but it was before the Mongol invasion of Khwārazm in 1220. He had already completed his "ḥajj" (pilgrimage) at the time. At the approach of the Mongols, Kubrā ordered all his students to return to their homes. Saʿd al-Dīn's "ijāza" was issued around this time. Saʿd al-Dīn appears to have returned to his uncle (then in Mosul) shortly before the latter's death in 1220. He eventually returned to Jabal Qāsiyūn, where he taught Ṣadr al-Dīn al-Qūnawī, who relayed Saʿd al-Dīn's works to his step-father Ibn al-ʿArabī, who is said to have admired them.