Narrated Mu’awiyah ibn Hayadah: I said: Apostle of Allah! To whom should I show kindness? He replied: Your mother, next your mother, next your mother, and then comes your father, and then your relatives in order of relationship. The Apostle of Allah (peace be upon him) said: If a man asks his slave whom he freed for giving him property which is surplus with him and he refuses to give it to him, the surplus property which he refused to give will be called on the Day of resurrection as a large bald snake.

Sunan of Abu-Dawood – Book 41 Hadith 5120