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." Instead, he would say to them, "May Allah guide you and set your affairs right."
حدثنا وكيع حدثنا سفيان وعبد الرحمن عن سفيان عن حكيم بن ديلم
كانت اليهود يتعاطسون عند النبي ﷺ رجاء أن يقول لهم يرحمكم الله فكان يقول لهم يهديكم الله ويصلح بالكم
Its isnad is sahih, and Hakeem bin Daylam is trustworthy, his hadith appears in Bukhari. The hadith was narrated by Bukhari 10/608, no. 6224, Fath al-Bari, in Adab, "responding to the sneezer," and Abu Dawud 5/291, no. 5038, and Tirmidhi 5/82, no. 2739, who said, hasan sahih, and Tabarani in al-Kabir 12/411.