The Jews used to deliberately sneeze in the presence of the Prophet ﷺ, hoping he would say to them, "May Allah have mercy on you." But he would say instead, "May Allah guide you and set your affairs right."
كان اليهود يتعاطسون عند النبي ﷺ يرجون أن يقول لهم: يرحمكم الله، فيقول: يهديكم الله ويصلح بالكم.
Reported by Abu Dawud (5038), Tirmidhi (2739), Ahmad (19586), Bukhari in Adab al-Mufrad (940), and Nasai in Amal al-Yawm wal-Layla (232/M), and Hakim graded it sahih (4/268), all of them via Sufyan Thawri, from Hakeem bin Daylam, from Abu Burda, from his father Abu Musa, who narrated it.Tirmidhi said, "This is a hasan sahih hadith."Hakim said, "This is a hadith with a connected chain of transmission," and its chain is hasan because of Hakeem bin Daylam, for he is truthful.