Sahih Bukhari Volume 004, Book 053, Hadith Number 407.

Narated By Asma 'bint Abi Bakr : During the period of the peace treaty of Quraish with Allah's Apostle, my mother, accompanied by her father, came to visit me, and she was a pagan. I consulted Allah's Apostle, "O Allah's Apostle! My mother has come to me and she desires to receive a reward from me, shall I keep good relation with her?" He said, "Yes, keep good relation with her."