 حَدَّثَنِی أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ أَبِیهِ عَنْ مُحَمَّدِ بْنِ أَحْمَدَ عَنْ إِبْرَاهِیمَ بْنِ إِسْحَاقَ عَنْ عَبْدِ اللَّهِ بْنِ أَحْمَدَ عَنْ مُحَمَّدِ بْنِ سِنَانٍ عَنِ الرِّضَا ع قَالَ: الْمَرَضُ لِلْمُؤْمِنِ تَطْهِیرٌ وَ رَحْمَهٌ وَ لِلْکَافِرِ تَعْذِیبٌ وَ لَعْنَهٌ وَ إِنَّ الْمَرَضَ لَا یَزَالُ بِالْمُؤْمِنِ حَتَّی لَا یَکُونَ عَلَیْهِ ذَنْبٌ.
1. It was narrated to me by Ahmad b. Muhammad from his father from Muhammad b. Ahmad from Ibrahim b. Ishaq from Abdillah b. Ahmad from Muhammad b. Sinan from al-Ridha (a.s.) who said: “Illness purifies a believer. It is a mercy for him and a chain and curse for an infidel. A believer remains ill till the time his sins are forgiven.”