It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that when he sneezed and «يرحمك الله» was said to him, he would say: May Allah have mercy on us and on you, and may He forgive us and you as well.
Hadith Referenceالادب المفرد / كتاب العطاس والتثاؤب / 933
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : الموطأ للإمام مالك ، ح : 1522»
It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), he said: When any one of you sneezes, he should say «الحمد للہ رب العالمین», and the one who responds should say «يرحمك الله», then the one who sneezed should say: «يغفر الله لي ولكم» May Allah forgive me and you as well.
Hadith Referenceالادب المفرد / كتاب العطاس والتثاؤب / 934
Hadith Gradingالألبانی:صحيح الإسناد موقوفًا
Hadith Takhrij«صحيح الإسناد موقوفًا : المعجم الكبير للطبراني : 162/10»
It is narrated from Sayyiduna Salamah bin Akwa’ (may Allah be pleased with him), he said that a man sneezed in the presence of the Prophet (peace and blessings of Allah be upon him), so the Prophet (peace and blessings of Allah be upon him) said: «يرحمك الله». When he sneezed again, the Prophet (peace and blessings of Allah be upon him) said: "He has a cold."
Hadith Referenceالادب المفرد / كتاب العطاس والتثاؤب / 935
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : صحيح مسلم ، الزهد و الرقائق ، ح : 2993 - الصحيحة : 1330- رواه مسلم ، كتاب الزهد ، باب تشميت العاطس : 55 ، 2993 و الترمذي : 2743»