Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says regarding this statement of Allah Almighty, (Allah Almighty says:) "Mankind was one nation." Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: It means that at first all the people were followers of Islam. Al-Kalbi says: It means that at first all the people were upon disbelief.
Abu Ya'la recorded it, and al-Tabarani recorded it in abridged form; the narrators of Abu Ya'la are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التفسير / 10857
Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: Between Adam (peace be upon him) and Nuh (peace be upon him) there were ten centuries, and all those people remained upon a law of truth. Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: When Allah Almighty sent the Prophet (peace and blessings be upon him) and revealed His Book, then the people became one nation.
Al-Bazzar recorded it; its chain contains a narrator, Abd al-Samad bin al-Nu'man, whom Yahya bin Ma'in declared thiqah (trustworthy), while others say: He is not strong.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التفسير / 10858
Hadith Gradingمحدثین:إسناده صحيح, في « كشف الأستار » 3 / 41 برقم (2190) من طريق عبد الصمد بن النعمان ، حدثنا همام ، عن قتادة ، عن عكرمة ، عن ابن عباس... وهذا إسناد صحيح .