Omar ibn Said is widely known for fourteen manuscripts that he wrote in Arabic. Out of all of his Arabic manuscripts, he is best known for his autobiographical essay written in 1831. It describes some of the events of his life and includes reflections on his steadfast adherence to Islam and his openness towards other 'God fearing' people. On the surface the document may appear to be tolerant towards slavery, however Said begins it with Surat Al-Mulk, a chapter from the Qur'an, which states that only God has sovereignty over human beings.
Most of Said's other work consisted of Islamic manuscripts in Arabic, including a handwritten copy of some short chapters (surat) from the Qur'an that are now part of the North Carolina Collection in the Wilson Library at University of North Carolina at Chapel Hill. His Bible, a translation into Arabic published by a missionary society, which has notations in Arabic by Omar, is part of the rare books collection at Davidson College. Transcribing from memory, ibn Said made some mistakes in his work, notably at the start of Surat An-Nasr. Said was also the author of a letter dated 1819 and addressed to James Owen's brother, Major John Owen, written in Arabic and containing numerous Quranic references (including from the above-mentioned Surat Al-Mulk), which also includes several geometric symbols and shapes which point to its possible esoteric intentions. This letter, currently housed in Andover Theological Seminary, is reprinted in Allen Austin's African Muslims in Antebellum America: A Sourcebook.