Musnad Ahmad 788:130

'Affan and Bahz narrated to us, they said: Hammam narrated to us, Qatadah narrated to us, from Anas, that Abu Musa al-Ash'ari narrated to him, from the Prophet, peace and blessings of Allah be upon him, who said: "The likeness of the believer who reads the Quran is like the citron: its taste is good and its scent is good. And the likeness of the believer who does not read the Quran is like the date: its taste is good and it has no scent. And the likeness of the wicked person who reads the Quran is like the basil: its scent is good and its taste is bitter. And the likeness of the wicked person who does not read the Quran is like the colocynth: its taste is bitter and it has no scent."