Sahih Muslim 793
Sahih Muslim · Book 6: The Book of Prayer - Travellers · It is recommended to make one’s voice beautiful when reciting Qur’an
Abu Burda narrated on the authority of Abu Musa that the Messenger of Allah (ﷺ) had said to Abu Musa:
وَحَدَّثَنَا دَاوُدُ بْنُ رُشَيْدٍ ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ ، حَدَّثَنَا طَلْحَةُ ، عَنْ أَبِي بُرْدَةَ ، عَنْ أَبِي مُوسَى ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لأَبِي مُوسَى " لَوْ رَأَيْتَنِي وَأَنَا أَسْتَمِعُ لِقِرَاءَتِكَ الْبَارِحَةَ لَقَدْ أُوتِيتَ مِزْمَارًا مِنْ مَزَامِيرِ آلِ دَاوُدَ " .
If you were to see me, as I was listening to your recitation (of the Qur'an) yester-night (you would have felt delighted). You are in fact endowed with a sweet voice like that of David himself.