Al-Adab Al-Mufrad, Book 1, Hadith 3 (In-Book) ⓘ
Bahz ibn Hakim's grandfather said, "I asked, 'Messenger of Allah, to whom should I be dutiful?' 'Your mother,' he replied. I asked, 'Then whom?' 'Your mother,' he replied. I asked, 'Then whom?' 'Your mother,' he replied. I asked, 'Then to whom should I be dutiful?' 'Your father,' he replied, 'and then the next closest relative and then the next.'"
حَدَّثَنَا أَبُو عَاصِمٍ، عَنْ بَهْزِ بْنِ حَكِيمٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، قُلْتُ: يَا رَسُولَ اللهِ، مَنْ أَبَرُّ؟ قَالَ: أُمَّكَ، قُلْتُ: مَنْ أَبَرُّ؟ قَالَ: أُمَّكَ، قُلْتُ: مَنْ أَبَرُّ؟ قَالَ: أُمَّكَ، قُلْتُ: مَنْ أَبَرُّ؟ قَالَ: أَبَاكَ، ثُمَّ الأَقْرَبَ فَالأَقْرَبَ.
also referenced under: Hadith 3 (Reference) & Book 1, Hadith 3 (English)