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In Khartank, Muhammad al-Bukhari diligently devoted the latter phase of his life to collecting and meticulously scrutinizing hadith, earning him the title of "Amir al-Mu'minin fi'l-Hadith" (Leader of the Believers in Hadith). His commitment to preserving the Prophet Muhammad's teachings led to the compilation of the renowned hadith collection known as "Sahih al-Bukhari," widely regarded as one of the most authentic and revered works in Islamic literature.