Sahih Muslim Book 25, Hadith 12
What makes you weep? He said: I am afraid I may die in the land from where I migrated as Sa'd b. Khaula had died. Thereupon Allah's Apostle (ﷺ) said: O Allah, grant health to Sa'd. O Allah, grant health to Sad. He repeated it three times. He (Sa'd) said: Allah's Messenger, I own a large property and I have only one daughter as my inheritor. Should I not will away the whole of my property? He (the Holy Prophet) said: No. He said: (Should I not will away, ) two-thirds of the property? he (the Holy Prophet) said: No. He (Sa'd) (again) said: (Should I not will away) half (of my property)? He said: No. He (Sa'd) said: Then one-third? Thereupon he (the Holy Prophet) said: (Yes), one-third, and one-third is quite substanial. And what you spend as charity from your property is Sadaqa and flour spending on your family is also Sadaqa, and what your wife eats from your property is also Sadaqa, and that you leave your heirs well off (or he said: prospreous) is better than to leave them (poor and) begging from people. He (the Holy Prophet) pointed this with his hands.
Allah's Apostle (ﷺ) visited me during my illness. I said: I am willing away the whole of my property. He said: No. I said: Then half? He said: No. I said: Should I will away one-third? He said: Yes, and even one-third is enough.
They said: Sa'd fell ill in Mecca. Allah's Messenger (ﷺ) visited him to inquire after his health. The rest of the hadith is the same.