Sahih Muslim 792
Sahih Muslim · Book 6: The Book of Prayer - Travellers · It is recommended to make one’s voice beautiful when reciting Qur’an
Abu Huraira is reported to have heard Allah's Messenger (ﷺ) as saying:
حَدَّثَنِي بِشْرُ بْنُ الْحَكَمِ ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ مُحَمَّدٍ ، حَدَّثَنَا يَزِيدُ، - وَهُوَ ابْنُ الْهَادِ - عَنْ مُحَمَّدِ بْنِ إِبْرَاهِيمَ ، عَنْ أَبِي سَلَمَةَ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " مَا أَذِنَ اللَّهُ لِشَىْءٍ مَا أَذِنَ لِنَبِيٍّ حَسَنِ الصَّوْتِ يَتَغَنَّى بِالْقُرْآنِ يَجْهَرُ بِهِ " .
Allah does not listen to anything, (more approvingly) as He listens to a Prophet reciting loudly the Qur'an in a sweet voice.