It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever narrates something and someone sneezes in his presence (that is, during that time), then that statement is true and correct."
The chain of this hadith is weak; its narrator Mu'awiyah bin Yahya al-Sadafi is weak according to the majority, and Baqiyyah bin al-Walid is a mudallis; Imam al-Albani (may Allah have mercy on him) declared it mawdu' (fabricated) in his book "Silsilat al-Ahadith al-Da'ifah", and Imam al-Nawawi and other researchers have also rejected its authenticity. (Takhrij: Musnad Abi Ya'la: 2595)
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الأدب / 2595
Hadith Gradingمحدثین:إسناده موضوع
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :موضوع. » «أخرجه المعجم الأوسط للطبراني برقم: 6505، وأخرجه مجمع الزوائد ومنبع الفوائد برقم: 12913، وأخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 5521»
It is narrated from Sayyidah Aishah (may Allah be pleased with her) that a man sneezed in the presence of the Messenger of Allah (peace and blessings be upon him) and asked: O Messenger of Allah, what should I say (on such an occasion)? He (peace and blessings be upon him) said: "Say: 'Al-hamdu lillah' (All praise is for Allah)." Then the people present said: O Messenger of Allah, what should we say to him (in reply)? He (peace and blessings be upon him) said: "Say: 'Yarhamuk Allah' (May Allah have mercy on you)." The man then asked: What reply should I give them (in return)? He (peace and blessings be upon him) said: "Say: 'Yahdikumullahu wa yuslihu balakum' (May Allah guide you and set your affairs right)."
The narrator Muhammad bin Abi Ma'shar in the chain of this hadith is weak; however, the etiquette of sneezing and these words are established by other sahih blessed hadith.
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الأدب / 2596
Hadith Gradingمحدثین:إسناده صحيح
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده صحيح. » «أخرجه مسند أحمد برقم: 23975، وأخرجه شرح معاني الآثار برقم: 7025، وأخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 5520»