(163) بَابُ فَضْلِ الْكَبِيرِ
Abu Hurayra reported that the Prophet, may Allah bless him andgrant him peace, said, "Anyone who does not show mercy to our childrennor acknowledge the right of our old people is not one of us."
Reference: Al-Adab Al-Mufrad 353
In-book reference: Book 18, Hadith 1
English translation: Book 18, Hadith 353