The origins of Harb tribe came from the 2nd century of the Islamic calendar, when Qahtani tribes emigrated from the south of Arabian Peninsula to Hijaz around 131 AH for water and land space after some battles with their cousins Banu Ar-Rabi'ah bin Saad.
On 21 October 2008, Susan J. Crawford, the Bush official in charge of convening the Office of Military Commissions, announced that the charges were dropped against Jabran Al Qahtani and four other captives, Binyam Mohamed, Ghassan al Sharbi, Sufyian Barhoumi, and Noor Uthman Muhammed.
In that period the Ghassānids, Lakhmids and Kindites were all Kahlānī and Qaḥṭānī vassal kingdoms appointed by the Byzantines, Persians and Ḥimyarites to protect their borders and imperial interests from the raids of the then-rising threat of the 'Adnānī tribes.
The latter were of Qahtani origin and spoke Yemeni-Arabic as well as Greek, and who protected the south-eastern frontiers of the Roman and Byzantine Empires in north Arabia.