Al-Matalib al-'Aliyah 2454 — Illness as expiation, the reward

It is narrated from Abu al-Ash'ath al-San'ani (may Allah have mercy on him) that he set out for the Grand Mosque of Damascus and arrived there at midday. There he met Sayyiduna Shaddad bin Aws (may Allah be pleased with him) and another man with him, and he asked: "May Allah have mercy on you both, where are you intending to go?" They both replied: "We are going here to visit a sick brother of ours." The narrator says: So he went along with them until they reached that sick man, and the two of them asked him: "How have you woken this morning?" He replied: "I have woken by the blessing of Allah and His bounty." At this Sayyiduna Shaddad (may Allah be pleased with him) said to him: "Rejoice at the expiation of sins and the shedding of faults, for I heard the Messenger of Allah (peace and blessings be upon him) saying: 'Allah, the Mighty and Majestic, says: Indeed, when I afflict one of My believing servants with a trial (of illness) and he praises Me for that trial, he rises from that bed of his as clean of sins as on the day his mother gave birth to him. And Allah, the Mighty and Majestic, says (to the angels): It is I who confined this servant of Mine and put him to trial, so continue for him the same reward that you used to continue for him in his state of health and well-being.'"
In the chain of this report in Musnad Abi Ya'la, there is criticism of Isma'il bin Ayyash's narration from Rashid bin Dawud; however, on the basis of other supporting reports this hadith reaches the grade of sahih li-ghayrihi (authentic due to supporting evidence).