Bahz bin Hakim narrates from his father, from his grandfather (may Allah be pleased with him), that he said: I said: O Messenger of Allah (peace and blessings be upon him)! To whom should I show the most kindness? He (peace and blessings be upon him) said: "To your mother." I said: Then who? He said: "Your mother." I said: Then who? He said: "Your mother." I said: Then who? He said: "Your father, then the nearest relative, and then the next nearest."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15756