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nasai-kubra:5243 – ʿUbaydullāh b. Saʿīd > Abū Usāmah

"I heard Abu Usamah say: 'I never saw any man more assiduous in seeking knowledge than 'Abdullah bin Al-Mubarak, not in Ash-Sham, Egypt, Yemen or the Hijaz.'" (Using translation from Nasāʾī 5752)  

الكبرى للنسائي:٥٢٤٣ – أَخْبَرَنَا عُبَيْدُ اللهِ بْنُ سَعِيدٍ قَالَ

سَمِعْتُ أَبَا أُسَامَةَ يَقُولُ «مَا رَأَيْتُ رَجُلًا أَطْلَبَ لِلْعِلْمِ مِنْ عَبْدِ اللهِ بْنِ الْمُبَارَكِ فِي الشَّامَاتِ وَمِصْرَ وَالْيَمَنِ وَالْحِجَازِ»  

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Collected by Nasāʾī
nasai:5752 – ʿUbaydullāh b. Saʿīd > Abū Usāmah

"I heard Abu Usamah say: 'I never saw any man more assiduous in seeking knowledge than 'Abdullah bin Al-Mubarak, not in Ash-Sham, Egypt, Yemen or the Hijaz.'"  

النسائي:٥٧٥٢ – أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ قَالَ

سَمِعْتُ أَبَا أُسَامَةَ يَقُولُ مَا رَأَيْتُ رَجُلاً أَطْلَبَ لِلْعِلْمِ مِنْ عَبْدِ اللَّهِ بْنِ الْمُبَارَكِ الشَّامَاتِ وَمِصْرَ وَالْيَمَنَ وَالْحِجَازَ