Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) say: "The one who recites the Qur'an aloud is like one who gives charity openly, and the one who recites the Qur'an quietly is like one who gives charity in secret."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4712