Ikrima narrated on the authority of Ibn ʿAbbas:

“When the Prophet—may Allah bless him and grant him peace—returned to Mecca and the season of pilgrimage came around, a number of the Ansar performed Hajj. The Prophet—peace and blessings be upon him—approached a group of them, recited the Quran to them, invited them to Allah, and informed them of the favor Allah had bestowed upon him. They were convinced, their hearts felt reassured by his call, and they recognized what they had been hearing from the People of the Book concerning him—his characteristics and the very message to which he was summoning them. Accordingly, they affirmed his truthfulness and believed in him. One of the means by which Allah guided the Ansar to such goodness was precisely the reports they had previously heard describing him. When they returned to their people, they began to invite them in secret, conveying the words of the Messenger of Allah—peace and blessings be upon him—and the light, guidance, and Quran with which Allah had sent him. They continued to accept Islam until hardly a single household remained without some of its members having embraced the faith without fail.”

Allah has mentioned this in the Quran, and He has stated that the People of the Book used to inform the Arabs about him and seek victory over them by means of his impending mission. Thus the People of the Book acknowledged his prophethood, spoke of it, and gave glad tidings of it before he was ever sent. Concerning this, the Exalted says, addressing the People of the Book: