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Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
ibnmajah:392 – Kurdūs b. Abū ʿAbdullāh al-Wāsiṭī > ʿAbd al-Karīm b. Rawḥ > Abū Rawḥ b. > Basah b. Saʿīd b. Abū ʿAyyāsh a freed slave of ʿUthmān b. ʿAffān from his father > Basah b. Saʿīd

"I used to help the Messenger of Allah perform ablution, when I was standing and he was sitting."  

ابن ماجة:٣٩٢ – حَدَّثَنَا كُرْدُوسُ بْنُ أَبِي عَبْدِ اللَّهِ الْوَاسِطِيُّ حَدَّثَنَا عَبْدُ الْكَرِيمِ بْنُ رَوْحٍ حَدَّثَنَا أَبِي رَوْحُ بْنُ عَنْبَسَةَ بْنِ سَعِيدِ بْنِ أَبِي عَيَّاشٍ مَوْلَى عُثْمَانَ بْنِ عَفَّانَ عَنْ أَبِيهِ عَنْبَسَةَ بْنِ سَعِيدٍ

عَنْ جَدَّتِهِ أُمِّ أَبِيهِ أُمِّ عَيَّاشٍ وَكَانَتْ أَمَةً لِرُقَيَّةَ بِنْتِ رَسُولِ اللَّهِ ﷺ قَالَتْ كُنْتُ أُوَضِّئُ رَسُولَ اللَّهِ ﷺ أَنَا قَائِمَةٌ وَهُوَ قَاعِدٌ  

See similar narrations below:

Collected by Ṭabarānī
tabarani:21795 – Muḥammad b. ʿAbdullāh al-Ḥaḍramī > Kurdūs b. Muḥammad al-Wāsiṭī > ʿAbd al-Karīm b. Rawḥ > Abū Rawḥ b. > Basah from his father > Basah b. Saʿīd

"I used to help the Messenger of Allah perform ablution, when I was standing and he was sitting." (Using translation from Ibn Mājah 392)  

الطبراني:٢١٧٩٥ – حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللهِ الْحَضْرَمِيُّ ثنا كُرْدُوسُ بْنُ مُحَمَّدٍ الْوَاسِطِيُّ ثنا عَبْدُ الْكَرِيمِ بْنُ رَوْحٍ حَدَّثَنِي أَبِي رَوْحُ بْنُ عَنْبَسَةَ عَنْ أَبِيهِ عَنْبَسَةَ بْنِ سَعِيدٍ

عَنْ جَدَّتِهِ أُمِّ أَبِيهِ أُمِّ عَيَّاشٍ وَكَانَتْ أَمَةً لِرُقَيَّةَ بِنْتِ رَسُولِ اللهِ ﷺ قَالَتْ «كُنْتُ أُوَضِّئُ النَّبِيَّ ﷺ وَأَنَا قَائِمَةٌ وَهُوَ قَاعِدٌ»