(14) باب فَضْلِ النَّفَقَةِ وَالصَّدَقَةِ عَلَى الْأَقْرَبِينَ وَالزَّوْجِ وَالْأَوْلَادِ وَالْوَالِدَيْنِ وَلَوْ كَانُوا مُشْرِكِينَ
Asma' bint Abu Bakr reported:
My mother who was a polytheist came to me when he (the Holy Prophet) entered into treaty with, the Quraish (of Mecca). I inquired from the Messenger of Allah (ﷺ) saying: Messenger of Allah, there has come to me my mother and she is inclined; should I (in this state of her mind) show her kindness? He said: Yes, treat her kindly.
Reference: Sahih Muslim 1003 b
In-book reference: Book 12, Hadith 62
USC-MSA web (English) reference(deprecated numbering scheme): Book 5, Hadith 2195