Mukhtasar Bukhari

Narrated Sa'd bin Abi Waqqas (may Allah be pleased with him): I heard the Prophet (peace and blessings of Allah be upon him) say: "Whoever claims someone other than his (real) father as his father, knowing that he is not his father, Paradise is forbidden for him." (The narrator of the hadith, Uthman, said:) I narrated this hadith to Abu Bakrah (may Allah be pleased with him), and he said: My ears also heard this hadith from the Prophet (peace and blessings of Allah be upon him) and I remembered it.

Narrated by Sayyiduna Abu Huraira (may Allah be pleased with him) from the Noble Prophet (peace and blessings of Allah be upon him) that he (peace be upon him) said: "(O people!) Do not disown your fathers, for disowning one's father is disbelief."