Correct Islamic Doctrine (Al-'Aqida al-Sahiha) & Islamic Doctrine (Al-'Aqida Ahl al-Islam).
Ibn Khafif (~276 - 371 H) Muhammad ibn Khafif ibn Asfakshad, Abu 'Abd Allah al-Shirazi al-Dibbi al-Shafi'I al-Sufi. Al-Sulami said of him, "The Folk (I.e. the Sufis) do not have anyone older than him nor more complete in his state and reality today." He took speculative theology (kalam) from al-Ash'ari, jurisprudence (fiqh) from Ibn Surayj, and Sufism (tasawwuf) from Ruwaym, al-Jariri, and Abu al-'Abbas ibn Ata. Al-Dhahabi said of him, "He is -- one of the most knowledgeable shaykhs in the external sciences (ulum al-zahir)." Ibn Taymiyya names him among the great Sufi representatives of the Sunna.
Ibn Khafif said, "In my beginnings I would recite in one cycle of prayer al-Ikhlas [Quranic chapter 112] ten thousand times, or recite the entire Qur`an in one cycle of prayer." Al-Sulami said, "Abu 'Abd Allah [ibn Khafif] came from a family of princes, but he practiced asceticism (zuhd) to the point that he said, 'I would collect rags from refuse-heaps, wash them, and mend whatever I could use for clothing, and I spent fourteen months breaking my fast at night with a handful of beans.'"
Ibn 'Arabi (555 - 630 H) Abu Bakr Muhammad ibn al-'Arabi al-Hatimi al-Tai, entitled Muhyi al-Din ("Reviver of the Faith"), was born in Murcia in southern Spain, to an Arab family and educated in Seville. At twenty he already possessed profound spiritual insights.
Until 588 H (1198 CE) Ibn 'Arabi spent his life in Andalusia and North Africa meeting other scholars and Sufis and occasionally engaging in debates. That year he had a vision ordering him to depart for the East where he was to spend the rest of his days. After years of traveling through Arabia, Egypt, Asia Minor and elsewhere, he became a teacher of great renown.
Titled "The Greatest Shaykh", Ibn 'Arabi authored over 280 works, including his magnum opus, the twelve volume "Makkan Revelations" an extensive compendium of Islam's esoteric sciences, the doctrines of tasawwuf and a diary of his own spiritual experiences surpassing anything of its kind.