Al-Ghazali was thirty-eight years old and stood at the top of the Sunni scholarly world. He was the chief professor at the Nizamiyya Madrasa of Baghdad, an institution the Seljuk vizier Nizam al-Mulk had built as the flagship of Sunni orthodoxy against the Ismaili challenge from the west. To be given the chair of the Baghdad Nizamiyya was to be given the intellectual command of Sunni Islam. Al-Ghazali held it. Every day he taught three hundred students in the main lecture hall. Every day scholars came from across the Muslim world to hear him. He had written hundreds of thousands of words on jurisprudence, theology, logic, and philosophy. He was, by every external measure, the successful man he had been trained to be.
One day, in the middle of a lecture, his tongue would not move. The words he was going to speak did not come. He stood in front of his class in silence. The students waited. He did not know what to say. He walked out.
He described the moment later in his own autobiography, Al-Munqidh min al-Dalal, the Deliverer from Error. He wrote: I looked into my motives, and I saw that I was teaching for the sake of position, and for the sake of being praised, and for the sake of being called a great scholar. Not for the sake of Allah. And I could not go on. My tongue would not obey me.
The realization did not release him immediately. He wrote: for six months I was between two states. Sometimes my heart chose Allah, sometimes it chose position. I lost the ability to eat. I lost the ability to drink. My legs would not hold me when I stood to teach. The doctors told me that my condition was caused by grief, and they said the only cure was to remove the grief from my heart. But they did not know what the grief was.
Finally he acted. He told his family he was going on hajj. He told the Sultan he was traveling on a personal matter. He gave away most of his wealth, retained just enough for himself and enough to leave to his children, and disappeared. He did not go to Mecca that year. He went to Damascus. He entered the Umayyad Mosque and did not leave it for months. He climbed the minaret every morning to be alone with Allah and he prayed. Then he moved to Jerusalem and prayed under the Dome of the Rock. Then he went to Mecca and Madinah for hajj. Then he wandered.
The wandering lasted eleven years. Nobody in Baghdad knew where he was. His enemies said he had lost his mind. His students said he had died. He was in Damascus. He was in Jerusalem. He was in the sanctuary of the Prophet ﷺ. He was in Tus, quietly, in a rented cell.
During those eleven years he wrote his greatest work. It is called Ihya Ulum al-Din, the Revival of the Religious Sciences. It is forty books long. It is divided into four quarters: the ibadat (acts of worship), the adat (matters of daily life), the muhlikat (the destroyers of the soul), and the munjiyat (the savers of the soul). It takes the whole of the Islamic scholarly tradition, the fiqh and the kalam and the hadith, and puts them next to the Sufi experience of tasting, dhawq, the direct taste of Allah in the heart. It says: the outer law and the inner experience are the same religion, and neither without the other is complete.
The Ihya became the most influential Sunni book of religion after the Quran and the hadith collections. Every serious student of Sunni Islam has read it. It is still taught in madrasas today. When Muslim scholars want to argue that Sufism is legitimate and orthodox, they cite the Ihya. When they want to argue that jurisprudence must be spiritually alive, they cite the Ihya. When they want to argue that the outer religion cannot exist without the inner, they cite the Ihya.
Al-Ghazali finally returned to Baghdad briefly, then went back to Tus, his hometown, near Mashhad. He taught quietly there for a few years. He died in 1111 CE. He is buried in Tus. On his grave they wrote the title he had earned during those eleven silent years: Hujjat al-Islam, the Proof of Islam.
What the story teaches. A career can be built at the top of the world and be built on the wrong foundation. Al-Ghazali did not lose his ability to teach because he had lost his knowledge. He lost it because his knowledge was for the wrong audience. He was teaching to impress. When he saw that, the tongue would not move any longer. The eleven-year disappearance was not a retreat. It was the actual work of the second half of his life. He came back with a book that has fed Muslim spiritual life for nine hundred years. The lesson is: sometimes the throat closing in the middle of a public sentence is Allah's way of saving your life.