Bahz ibn Hakim reported on the authority of his father and his grandfather that he asked, “0 Messenger of Allah! who is most deserving (of kind treatment)?” He said, “Your mother.” He asked, ‘Who next?” He said, “Your mother.” He asked, “And after her?” He (again) said, “Your mother.” He asked, “And next?” He said, “Your father. Then, the nearest, followed by the nearest.”
[Bukhari 5971, Muslim 2548]