Abu Uthman says that I heard from Sayyiduna Sa’d (may Allah be pleased with him) — who was the first to shoot an arrow in the way of Allah — and Sayyiduna Abu Bakr (may Allah be pleased with him) — who climbed the fortification of Ta’if — both, that we heard the Prophet (peace and blessings be upon him) say: “Whoever claims someone as his father other than his (real) father, knowing that he is not his father, Paradise is forbidden for him.”
Hadith Referenceمسند احمد / مسند باقي العشرة المبشرين بالجنة / 1497