Sahih Bukhari: Hadith 5223

Allah's Messenger (ﷺ) said, "The example of a Believer who recites the Qur'an, is that of a citron which smells good and tastes good; And the example of a Believer who does not recite the Qur'an, is that of a date which has no smell but tastes sweet; and the example of a hypocrite who recites the Qur'an, is that of an aromatic plant which smells good but tastes bitter; and the example of a hypocrite who does not recite the Qur'an, is that of a colocynth plant which has no smell and is bitter in taste."