The story of Muhammad's encounter with Bahira is found in the works of the early Muslim historians Ibn Hisham, Ibn Sa'd, and al-Tabari, whose versions differ in some details. When Muhammad was either nine or twelve years old, he met Bahira in the town of Bosra in Syria during his travel with a Meccan caravan, accompanying either Abu Bakr or Ali. When the caravan was passing 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 was to become a prophet. According to one version, those were the stigmata
that Bahira found on the young Muhammad; other variants of the story say that it was a miraculous movement of a cloud or an unusual behavior of a branch that kept shadowing Muhammad regardless of the time of the day.
The monk revealed his visions of Muhammad's future to the boy's companion (Abu Bakr or Ali), warning him to preserve the child from the Jews (in Ibn Sa'd's version) or from the Byzantines (in al-Tabari's version). 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; the standard Islamic view is that Christians corrupted the gospels, in part by erasing any references to Muhammad.
In the Christian polemics against Islam, Bahira became a heretical monk, whose errant views inspired the Qur'an. The names and religious affiliations of the monk vary in different Christian sources. For Al-Kindi, who calls him Sergius and writes that he later called himself Nestorius, Bahira was a Nestorian. 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 Jacobite or an Arian. 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. Christian 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 or contemporary Jews.
Below are some confessions of the monk Bahira that he inspired by the Quran, from the book; (R.Gottheil. A Christian Bahira Legend)
from, R.Gottheil. A Christian Bahira Legend.