كتاب فضائل الصحابة رضى الله تعالى عنهم
44
The Book of the Merits of the Companions
(52)
Chapter: The Virtues Of the Sahabah, Then Those Who Come After Them, Then Those Who Come After Them
(52)
باب فَضْلِ الصَّحَابَةِ ثُمَّ الَّذِينَ يَلُونَهُمْ ثُمَّ الَّذِينَ يَلُونَهُمْ ‏‏

Abdullah reported Allah's Messenger (ﷺ) as saying:

The best of my Umma would be those of the generation nearest to mine. Then those nearest to them, then those nearest to them, then people would come whose witness would precede the oath and the oath will precede the witness. Hannad has not made the mention of Qarn in his narration. Qutaiba said that, instead of the word Qaum, the word Aqwam has been used.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَهَنَّادُ بْنُ السَّرِيِّ، قَالاَ حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ مَنْصُورٍ، عَنْ إِبْرَاهِيمَ بْنِ يَزِيدَ، عَنْ عَبِيدَةَ السَّلْمَانِيِّ، عَنْ عَبْدِ اللَّهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ خَيْرُ أُمَّتِي الْقَرْنُ الَّذِينَ يَلُونِي ثُمَّ الَّذِينَ يَلُونَهُمْ ثُمَّ الَّذِينَ يَلُونَهُمْ ثُمَّ يَجِيءُ قَوْمٌ تَسْبِقُ شَهَادَةُ أَحَدِهِمْ يَمِينَهُ وَيَمِينُهُ شَهَادَتَهُ ‏"‏ ‏.‏ لَمْ يَذْكُرْ هَنَّادٌ الْقَرْنَ فِي حَدِيثِهِ وَقَالَ قُتَيْبَةُ ‏"‏ ثُمَّ يَجِيءُ أَقْوَامٌ ‏"‏ ‏.‏
Reference : Sahih Muslim 2533 a
In-book reference : Book 44, Hadith 298
USC-MSA web (English) reference : Book 31, Hadith 6150
  (deprecated numbering scheme)