Sahih Bukhari

Narrated Zainab:(the daughter of Um Salama) My mother said, ""O Allah's Messenger (ﷺ)! Shall I receive a reward if I spend for the sustenance of Abu Salama's offspring, and in fact they are also my sons?"" The Prophet (ﷺ) replied, ""Spend on them and you will get a reward for what you spend on them