Sahih Bukhari Volume 007, Book 064, Hadith Number 282.

Narrated By Um Salama : I said, "O Allah's Apostle! Shall I get a reward (in the Hereafter) if I spend on the children of Abu Salama and do not leave them like this and like this (i.e., poor) but treat them like my children?" The Prophet said, "Yes, you will be rewarded for that which you will spend on them."