The Book of the Commencement of the Prayer
11/82. Chapter:
Elongating the sounds when reciting Quran
Sunan an-Nasai
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، قَالَ حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ، عَنْ قَتَادَةَ، قَالَ سَأَلْتُ أَنَسًا كَيْفَ كَانَتْ قِرَاءَةُ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ كَانَ يَمُدُّ صَوْتَهَ مَدًّا .
It was narrated that Qatadah said: "I asked Anas: 'How did the Messenger of Allah (ﷺ) recite Quran?' He said: 'He used to elongate the sounds.'"
Reference : Sunan an-Nasa'i 1014In-book reference : Book 11, Hadith 139English translation : Vol. 2, Book 11, Hadith 1015