The Book of Bequests (Kitab Al-Wasiyya)
Muslim :: Book 13 : Hadith 4000
Ibn 'Abbas (Allah be pleased with them) said: (I wish) if people would reduce from third to fourth (part for making a will of their property), for Allah's Messenger (may peace be upon him) said: So far as the third (part) is concerned it is quite substantial. In the hadith transmitted on the authority of Waki (the words are)" large" or" much".