Sahih Adab al-Mufrad

It is narrated from Bahz bin Hakim, from his father, and he from his grandfather: I asked, "O Messenger of Allah! With whom should I behave kindly?" He said, "With your mother." I asked, "Then with whom should I behave kindly?" He said, "With your mother." I asked, "Then with whom should I behave kindly?" He said, "With your mother." I asked, "Then with whom should I behave kindly?" He said, "With your father, then those who are closest to you, then those who are next closest."

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them) that a man came to him and said: I proposed marriage to a woman, but she refused to marry me. Another man proposed to her, and she preferred to marry him. I was overcome with jealousy and killed that woman. Is there any repentance for me? He asked: Is your mother alive? The man replied: No. He said: Repent to Allah and seek closeness to Him as much as you are able. Ata bin Yasar says: I went and asked Sayyiduna Abdullah bin Abbas (may Allah be pleased with them): Why did you ask him whether his mother was alive? He replied: I do not know of any deed that brings one closer to Allah than being good to one’s mother.