Sahih Bukhari Volume 3, Book 47, Hadith Number 763.

Narated By Asma : Once I said, “O Allah’s Apostle! I have no property except what has been given to me by Az-Zubair (i.e. her husband). May I give in charity?” The Prophet said, “Give in charity and do not withhold it; otherwise Allah will withhold it back from you.”