Sayyiduna Abu Dharr (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Whoever knowingly attributes himself to someone other than his father has committed kufr (disbelief). Whoever claims what is not his is not one of us, and let him take his seat in Hellfire. And whoever accuses a man of disbelief or of being an enemy of Allah, while he is not like that, the charge will rebound on the one who made the claim, when (the accused) is not like that."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللعان / 15335
Abu Uthman narrates from Sayyiduna Sa'd (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever claims someone other than his father, knowing that he is not his father, Paradise is forbidden to him." The narrator says: I mentioned this to Sayyiduna Abu Bakrah (may Allah be pleased with him), and he said: My ears heard it and my heart retained it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللعان / 15336
Khalid narrates from Abu Uthman: When Sayyiduna Mu'awiyah (may Allah be pleased with him) made his claim regarding Ziyad, I met Sayyiduna Abu Bakrah (may Allah be pleased with him) and said: What is this that you have done? I heard Sayyiduna Sa'd (may Allah be pleased with him); he says: My ears heard this and my heart retained it, that he (peace and blessings be upon him) said: "Whoever, in Islam, claims someone (as his father), knowing that he is not his father, Paradise is forbidden to him." Sayyiduna Abu Bakrah (may Allah be pleased with him) said: I too heard it from him (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللعان / 15337