Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates this statement of the Noble Prophet (peace and blessings be upon him): "Do not boast about your ancestors from the time of ignorance. By the One in Whose hand is the life of Muhammad, for a man to have his nose filled with dust is better than for him to boast about those ancestors of his who died in the time of ignorance."
Hadith Referenceصحیح ابن حبان / كتاب الحظر والإباحة / 5775
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «التعليق الرغيب» (4/ 21).فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط الصحيح