I said, "Messenger of Allah, shall I bequeath all of my wealth?"He said, "No."I said, "Then two-thirds of it?"He said, "No."I said, "Then half of it?"He said, "No."I said, "Then a third?"He said, "A third, and even a third is a lot. That you leave your family well-off is better than leaving them destitute, begging from people."
حدثنا حسين بن محمد حدثنا جرير يعني ابن حازم عن عمه جرير يعني ابن زيد
قلت يا رسول الله أوصي بمالي كله قال لا قلت فثلثيه قال لا قلت فنصفه قال لا قلت فالثلث قال الثلث والثلث كبير أحدكم يدع أهله بخير خير له من أن يدعهم عالة على أيدي الناس
Its isnad is sahih. Jareer bin Hazim bin Zayd bin Abdullah al-Azdi is trustworthy, Bukhari related from him in his Sahih, and he wrote a biographical entry for him in al-Kabir 1/2/211-212. This hadith is an abridgment of 1046.