The Shaykh (Imam al-Bayhaqi) (may Allah have mercy on him) said: "It has been narrated from the Prophet (peace and blessings be upon him) that he (peace and blessings be upon him) said: 'Allah Almighty does not listen to anything as attentively as He listens to a prophet who recites the Qur'an with a beautiful, melodious voice.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / Q21040