Hadith 5:37
Abu Musa (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "When one of you sneezes and praises Allah (i.e., says Al-hamdu lillah), you should invoke Allah's Mercy upon him (i.e., say Yarhamuk-Allah); but if he does not praise Allah, you should not respond." [Muslim] .
وعن أبي موسي رضي الله عنه قال: سمعت رسول الله صلى الله عليه وسلم يقول: "إذا عطس أحدكم فحمد الله فشمتوه، فإن لم يحمد الله فلا تشمتوه" ((رواه مسلم)).