Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates this statement of the Noble Prophet (peace and blessings be upon him): "Indeed, the Jews were divided into 71 sects (the narrator is in doubt, perhaps these are the words) or were divided into 72 sects, and the Christians were likewise, and this nation will be divided into 73 sects."
Hadith Referenceصحیح ابن حبان / كتاب التاريخ / 6730
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الصحيحة» (205 - 206).فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم