From Sahih Bukhari (Hadith 5978):
Narrated Asma' bint Abu Bakr:My mother came to me, hoping (for my favor) during the lifetime of the Prophet. I asked the Prophet, "May I treat her kindly?" He replied, "Yes." Ibn 'Uyaina said, "Then Allah revealed: 'Allah forbids you not with regards to those who fought not against you because of religion, and drove you not out from your homes, that you should show them kindness and deal justly with them
Reference: Bukhari 5978