Jami` at-Tirmidhi 2739
جامع الترمذي#2739SahihNarrated Abu Musa:The Jews used to sneeze in the presence of the Prophet (ﷺ) hoping that he would say: 'Yarhamukumullah (May Allah have mercy upon you).' So he said: 'Yahdikumullahu Wa Yuslihu Balakum (May Allah guide you and rectify your affairs)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 43:4