Al-Adab Al-Mufrad, Book 1, Hadith 6 (In-Book) ⓘ
Abu Hurayra reported: "A man came to the Prophet of Allah, may Allah bless him and grant him peace, and asked, 'What do you command me to do?' He replied, 'Be dutiful towards your mother.' Then he asked him the same question again and he replied, 'Be dutiful towards your mother.' He repeated it yet again and the Prophet replied, 'Be dutiful towards your mother.' Then he put the question a fourth time and the Prophet said, 'Be dutiful towards your father.'"
حَدَّثَنَا بِشْرُ بْنُ مُحَمَّدٍ، قَالَ: أَخْبَرَنَا عَبْدُ اللهِ، قَالَ: أَخْبَرَنَا يَحْيَى بْنُ أَيُّوبَ، قَالَ: حَدَّثَنَا أَبُو زُرْعَةَ، عَنْ أَبِي هُرَيْرَةَ، أَتَى رَجُلٌ نَبِيَّ اللهِ صلى الله عليه وسلم فَقَالَ: مَا تَأْمُرُنِي؟ فَقَالَ: بِرَّ أُمَّكَ، ثُمَّ عَادَ، فَقَالَ: بِرَّ أُمَّكَ، ثُمَّ عَادَ، فَقَالَ: بِرَّ أُمَّكَ، ثُمَّ عَادَ الرَّابِعَةَ، فَقَالَ: بِرَّ أَبَاكَ.
also referenced under: Hadith 6 (Reference) & Book 1, Hadith 6 (English)