From Sahih Bukhari (Hadith 5023):
Narrated Abu Huraira:Allah's Messenger (ﷺ) said, "Allah does not listen to a prophet as He listens to a prophet who recites the Qur'an in a pleasant tone." The companion of the sub-narrator (Abu Salama) said, "It means, reciting it aloud
Reference: Bukhari 5023