Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) says: Whoever says that the Messenger of Allah (peace and blessings of Allah be upon him) concealed anything from the commands of Allah, he is a liar, because Allah the Exalted says: "O Messenger! Convey whatever has been revealed to you from your Lord..."

Narrated Abdullah bin Mas'ud (may Allah be pleased with him):
We were with the Messenger of Allah (peace and blessings of Allah be upon him) in jihad and we had no women with us (and we could not bear separation from women), so we said: Should we get ourselves castrated? The Prophet (peace and blessings of Allah be upon him) forbade us from that and then allowed us to marry women temporarily (mut'ah) by giving a garment as a dowry. Then Abdullah (may Allah be pleased with him) recited this verse: "O you who believe! Do not make unlawful the good things which Allah has made lawful for you..." __QUR_N__ (Temporary marriage was made unlawful at the battle of Khaybar. See the Book: On the Description of Battles... Chapter: The Description of the Battle of Khaybar...) __REF_N__

Sayyiduna Anas bin Malik (may Allah be pleased with him) says that we had nothing except date wine. I was standing and serving this wine to Abu Talha and such-and-such persons when a man came and said, "Do you have any news?" All of them asked, "What is the matter?" He said, "Wine has been made unlawful." Then those (who were drinking wine) said, "Throw these cups of wine onto the ground." Sayyiduna Anas (may Allah be pleased with him) says that after this, no one inquired about wine nor drank it.

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."