Sahih Muslim
The Book Pertaining to Judicial Decisions (Kitab Al-Aqdiyya)
Book Number: 018 / Hadith Number: 4267
Sa'd b. Ibrahim reported: I asked Qasim b. Muhammad about a person who had three dwelling houses and he willed away the third part of every one of these houses; he (Qasim b. Muhammad) said: All of them could be combined in one house; and then said: 'A'isha informed me that Allah's Messenger (may peace be upon him) said: He who did any act for which there is no sanction from our behalf, that is to be rejected.