The story of Muhammad's encounter with Bahira occurs in the works of the early Muslim historiansIbn Hisham, Ibn Sa'd al-Baghdadi, and Muhammad ibn Jarir al-Tabari, whose versions differ in some details. The young Muhammad, then either nine or twelve years old, met Bahira in the town of Bosra in Syria while travelling with a Meccan caravan, accompanying his uncle Abu Talib ibn ‘Abd al-Muttalib. When the caravan passed by his cell, the monk invited the merchants to a feast. They accepted the invitation, leaving the boy to guard the camel. Bahira, however, insisted that everyone in the caravan should come to him. Then a miraculous occurrence indicated to the monk that Muhammad would become a prophet. The movement of a cloud that kept shadowing Muhammad regardless of the time of the day drew Bahira's attention. The monk revealed his visions of Muhammad's future to the boy's uncle, warning him to preserve the child from the Jews or from the Byzantines. Both Ibn Sa'd and al-Tabari write that Bahira found the announcement of the coming of Muhammad in the original, unadulterated gospels, which he possessed. A similar tradition is attributed to Ibn Shihab al-Zuhri in the works of the early ahadith compiler ‘Abd al-Razzaq al-San‘ani, in which the unnamed figure is a rabbi of Tayma instead of a Christian Syrian monk. The rabbi warns Abu Talib against bringing Muhammad to Syria, as he predicts that Muhammad will be killed by the Syrian Jews if they proceed. Abu Talib returns back to Mecca with his nephew. Later Islamic writers gave the rabbi the name of Bahira.
In the Christian tradition Bahira became a heretical monk, whose errant views inspired the Qur'an. Bahira is at the center of the Apocalypse of Bahira, which exists in Syriac and Arabic which makes the case for an origin of the Qur'an from Christian apocrypha. Certain Arabist authors maintain that Bahira's works formed the basis of those parts of the Qur'an that conform to the principles of Christianity, while the rest was introduced either by subsequent compilers such as Uthman Ibn Affan or contemporary Jews and Arabs. The names and religious affiliations of the monk vary in different Christian sources. For example, John of Damascus, a Christian writer, states that Muhammad "having chanced upon the Old and New Testaments and likewise, it seems, having conversed with an Arian monk, devised his own heresy." For Abd-al-Masih al-Kindi, who calls him Sergius and writes that he later called himself Nestorius, Bahira was a Nasorean, a group usually conflated with the Nestorians. After the 9th century, Byzantine polemicists refer to him as Baeira or Pakhyras, both being derivatives of the name Bahira, and describe him as an iconoclast. Sometimes Bahira is called a Syrian Jacobite or an Arian. The early Christian polemical biographies of Muhammad share in claiming that any supposed illiteracy of Muhammad did not imply that he received religious instruction solely from the angel Gabriel, and often identified Bahira as a secret, religious teacher to Muhammad.
