One-fifth of Booty to the Cause of Allah (Khumus)

Bukhari :: Book 4 :: Volume 53 :: Hadith 407

Narrated 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."