Sahih Bukhari Volume 6, Book 61, Hadith Number 538.

Narrated By Abu Musa Al-Ash’ari : The Prophet said, “The example of him (a believer) who recites the Qur’an is like that of a citron which tastes good and smells good. And he (a believer) who does not recite the Qur’an is like a date which is good in taste but has no smell. And the example of a dissolute wicked person who recites the Qur’an is like the Raihana (sweet basil) which smells good but tastes bitter. And the example of a dissolute wicked person who does not recite the Qur’an is like the colocynth which tastes bitter and has no smell.