Vocabulary of the ḥadith
– mā (a particle of negation): here it precedes a verbal clause.
– wiʿāʾ (container): accusative direct object. A wiʿāʾ is a receptacle in which something is placed; plural: awʿiyah.
– sharran (worse): accusative, serving as an adjective for wiʿāʾ.
– baṭnuhu (his belly): from the verb baṭana — “to be hidden.” The baṭn is the inner cavity of anything; here it is the opposite of ẓahr (back). It is masculine, with the plurals buṭūn and abṭān, so named because what it contains is concealed.

Lessons derived from the ḥadith
1 – Ibn Rajab said: It is related that the physician Ibn Abī Māsuwayh, when he read this ḥadith, remarked, “Had people acted on these words, they would have been spared illnesses and ailments, and the pharmacists’ shops would have had to close.” He said this because the root of every disease is overindulgence. Al-Ḥārith ibn Kalda observed, “Restrictive dieting is the essence of medicine, while gluttony is the essence of disease.” This explains some of the benefits of reducing one’s food intake and avoiding satiety for the sake of bodily soundness and health.

2 – Concerning the heart and its rectitude: eating little engenders tenderness of heart, sharpness of understanding, humility of the soul, and weakness of desire and anger, whereas abundant food produces the opposite.

3 – From the angle of character: disobedience to Allah is distant from the hungry person but near to the one who is full. Satiety defiles the heart and gives rise to exuberance, frivolity, and laughter. When the soul is hungry and thirsty, the heart becomes lucid and gentle; when it is full and sated, the heart is clouded.