اضيف ايضا وثيقة نصرانية من كتاب حياة الاسقف مار جبرئيل (متوفي سنة ٦٦٨ميلادية) Life of Gabriel of Qartmin و المكتوب في القرن الثامن الميلادي ، يصف المسلمين بابناء هاجر ، يصف امير المؤمنين عمر رضي الله عنه بحاكم ابناء هاجر :

This lord Gabriel went to the ruler (ahid shultana) of the sons of Hagar, who was Umar bar Khattab, in the city of Gezirta. He (Umar) received him with great joy, and after a few days the blessed man petitioned this ruler and received his signature to the statutes and laws, orders and prohibitions, judgements and precepts pertaining to the Christians, to churches and monasteries, and to priests and deacons that they do not give the poll tax, and to monks that they be freed from any tax (madatta). Also that the wooden gong should not be banned and that they might chant hymns before the bier when it comes out from the house to be buried, together with many [other] customs. This governor (shallita) was pleased at the coming to him of the blessed man and this holy one returned to the monastery with great joy
Gabriel of Qartmin, Life XII, 72 [p. 123