Sahih Muslim Book 4, Hadith Number 1743.

Chapter : Descending of tranquillity by the recitation of the Qur’an.

Abu Musa al-Ash’ari reported Allah’s Messenger (may peace be upon him) as saying: A believer who recites the Qur’an is like an orange whose fragrance is sweet and whose taste is sweet; a believer who does not recite the Qur’an is like a date which has no fragrance but has a sweet taste; and the hypocrite who recites the Qur’an is like a basil whose fragrance is sweet, but whose taste is bitter; and a hypocrite who does not recite the Qur’an is like the colocynth which has no fragrance and has a bitter taste.