Hadith 4735
وَعَنْ أَبِي مُوسَى قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «إِذَا عَطَسَ أَحَدُكُمْ فَحَمِدَ اللَّهَ فَشَمِّتُوهُ وَإِنْ لَمْ يَحْمَدِ اللَّهَ فَلَا تُشَمِّتُوهُ» . رَوَاهُ مُسلم
Abu Musa (may Allah be pleased with him) narrates: I heard the Messenger of Allah (peace and blessings be upon him) say: "When one of you sneezes and says 'Alhamdulillah' (All praise is due to Allah), then you should supplicate for him. But if he does not say 'Alhamdulillah', then do not supplicate for him." Narrated by Muslim.