Sahih Bukhari Volume 004, Book 051, Hadith Number 005.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 51. Wills and Testaments (Wasaayaa)
Narated By Sad bin Abu Waqqas : The Prophet came visiting me while I was (sick) in Mecca, ('Amir the sub-narrator said, and he disliked to die in the land, whence he had already migrated). He (i.e. the Prophet) said, "May Allah bestow His Mercy on Ibn Afra (Sad bin Khaula)." I said, "O Allah's Apostle! May I will all my property (in charity)?" He said, "No." I said, "Then may I will half of it?" He said, "No". I said, "One third?" He said: "Yes, one third, yet even one third is too much. It is better for you to leave your inheritors wealthy than to leave them poor begging others, and whatever you spend for Allah's sake will be considered as a charitable deed even the handful of food you put in your wife's mouth. Allah may lengthen your age so that some people may benefit by you, and some others be harmed by you." At that time Sad had only one daughter.