Sahih Muslim Book 032, Hadith Number 6303.
Chapter : Forbiddance of telling a lie and the cases in which telling of lie is permissible.
Humaid b. 'Abd al-Rahman b. 'Auf reported that his mother Umm Kulthum daughter of 'Uqba b. Abu Mu'ait, and she was one amongst the first emigrants who pledged allegiance to Allah's Apostle (may peace be upon him), as saying that she heard Allah's Messenger (may peace be upon him) as saying: A liar is not one who tries to bring reconciliation amongst people and speaks good (in order to avert dispute), or he conveys good. Ibn Shihab said he did not hear that exemption was granted in anything what the people speak as lie but in three cases: in battle, for bringing reconciliation amongst persons and the narration of the words of the husband to his wife, and the narration of the words of a wife to her husband (in a twisted form in order to bring reconciliation between them).