The Messenger of Allah ﷺ said, "When one of you sneezes, let him say, 'Praise be to Allah, Lord of the worlds.' Those around him should say, 'May Allah have mercy on you,' and he should reply, 'May Allah guide you and set your affairs right.'"
حدثنا عبد الله حدثني أبو بكر بن أبي شيبة حدثنا علي بن مسهر عن ابن أبي ليلى عن عيسى عن عبد الرحمن بن أبي ليلى
قال رسول الله ﷺ إذا عطس أحدكم فليقل الحمد لله رب العالمين وليقل من حوله يرحمك الله وليقل هو يهديكم الله ويصلح بالكم
Its isnad is hasan. Ali bin Mushir, with the mim vowelled with damma, the sin with sukun, and the ha with kasra, the Qurashi, the Kufan, was a reliable authority and hafiz. Ibn Abu Layla is Muhammad bin Abdul-Rahman, mentioned previously at 778. Isa is his brother Isa bin Abdul-Rahman bin Abu Layla, who is trustworthy, Ibn Main and others confirmed his reliability, and he has an entry in al-Jarh wal-Tadil 3/1/281 which corrects the blank space found in al-Tahdhib.Haythami mentioned this hadith in Majma al-Zawaid 8:57 and attributed it to Tabarani in al-Awsat, saying, "It contains Yahya bin Abdul-Hameed al-Hamani, who is daif." Perhaps he did not find the hadith in the Musnad, and so did not attribute it there before other sources, as is his custom. As for Yahya al-Hamani, some criticism has been directed at him, but it appears he is trustworthy, and Muslim included narrations from him in his Sahih.This hadith is not among the additional narrations, for Tirmidhi related it in 4:4 from the hadith of Ali, as will be explained at 995.