Musannaf Ibn Abi Shayba 22:260

Abu al-Ahwas narrated to us, from Abu Ishaq, from al-Harith, from Ali, who said: The likeness of the one who has gathered faith and gathered the Quran is like the citron, which is good in taste. And the likeness of the one who has not gathered faith and has not gathered the Quran is like the colocynth, which is evil in taste and evil in scent.