JABR جبر
A Christian servant of a family from Hazramaut – a convert to Islam – accused by the Quraish with having instructed the Prophet.
Surah xvi. 105: “We knew that they said ‘It is only some mortal that teaches him.’ The tongue of him they incline towards is barbarous, this is plain Arabic.”
Husain says Jabr was one of the Ahlu ‘l-Kitab, and was well read in the Taurat and Injil, and Muhammad used to hear him read these books as he passed his house.

Based on Hughes, Dictionary of Islam