Mukhtasar Bukhari

Narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that once the Prophet Muhammad (peace and blessings be upon him) delivered such a sermon that I had never heard a better sermon than that, and in the sermon he said: "If you knew what I know, you would laugh little and weep much." Upon hearing this, the companions (may Allah be pleased with them) covered their faces with their sheets and the sound of their weeping was heard. A man asked, "O Messenger of Allah! Who is my father?" The Prophet (peace and blessings be upon him) replied, "So-and-so was your father." At that time, this verse was revealed: "O you who believe! Do not ask about things which, if made plain to you, may cause you trouble...." __QUR_N__

´Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that` a group of people used to ask the Prophet (peace and blessings be upon him) questions in jest and mockery. Someone would say, "Who is my father?" Another would ask, "My she-camel is lost, where is it?" At that time, this verse was revealed: "O you who believe! Do not ask about things which, if made plain to you, may cause you trouble. But if you ask about them while the Qur'an is being revealed, they will be made plain to you. Allah has forgiven those (questions) that are past; and Allah is Oft-Forgiving, Most Forbearing."