It is his principal work. The information regarding creed found at the beginning of this work demonstrates to what extent he was well-versed in the science of kalām (Islamic theology). In addition, his work on hadith, also known as Bahru'l-fevâ'id and titled Meʿānī al-akhbār, is a commentary on hadiths related to Sufism (taṣawwuf), etiquette, and morality (akhlāq). Nearly all of these hadiths are comprised of those found in the authentic hadith collections.
Kushayri: Abū'l-Qāsim Zayn al-Islām ʿAbd al-Karīm Hawāzin ʿAbd al-Malik al-Kushayri was born in the year 376/986 in a region called Ustuwā near the border of Iran and Turkmenistan. He lost his father at a young age and was raised under the protection of a relative. He learned both religious sciences and martial arts such as horsemanship and the use of weapons. When he went to Nishapur with the aim of becoming a finance officer, Kushayri met Abū ʿAlī Daqqāq. At the request of his shaykh, he first studied Shāfiʿī jurisprudence, and only afterwards did he affiliate himself with the Sufi path. After the death of his spiritual guide, who was also his father-in-law, he affiliated himself with Abū Muḥammad Ḥusayn Sulamī, and began writing his tafsir (Qur'anic commentary) during Sulamī's lifetime.
Present in Nishapur at the founding of the Seljuk State, Kushayri had the opportunity to meet with Tughril Beg. During this period, he participated in the struggle of Ashʿarī scholars against the Muʿtazila. Beginning to teach hadith at the Nishapur madrasa, Kushayri continued these lessons until his death, and he passed away in this city in 465/1072, where he was also buried.
In scholarly circles, Kushayri is known as the person who brought Sufism (taṣawwuf) closer to the sharia (sharīʿa).