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Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
ahmad-zuhd:1491 – ʿAbdullāh > Aḥmad b. Ibrāhīm > Ibn ʿUlayyah > Yūnus

[Machine] Al-Hasan used to say, "The most harmful disease is the one that affects the heart, meaning desire."  

الزهد لأحمد:١٤٩١ – حَدَّثَنَا عَبْدُ اللَّهِ حَدَّثَنَا أَحْمَدُ بْنُ إِبْرَاهِيمَ حَدَّثَنَا ابْنُ عُلَيَّةَ عَنْ يُونُسَ قَالَ

كَانَ الْحَسَنُ يَقُولُ «شَرُّ دَاءٍ خَالَطَ قَلْبًا يَعْنِي الْهَوَى»