Sahih Bukhari Volume 4, Book 51, Hadith Number 3.

Narated By Talha bin Musarrif : I asked ‘Abdullah bin Abu Aufa “Did the Prophet make a will?” He replied, “No,” I asked him, “How is it then that the making of a will has been enjoined on people, (or that they are ordered to make a will)?” He replied, “The Prophet bequeathed Allah’s Book (i.e. Quran).”