It is narrated from Sayyiduna Abu Burdah (may Allah be pleased with him), he says: I went to my father, Sayyiduna Abu Musa Ash’ari (may Allah be pleased with him), he was in the house of Umm Kulthum, the daughter of Umm Fadl (she was his wife). I sneezed, but my father did not respond to me. However, when Umm Kulthum sneezed, he responded to her. When I returned to my mother, I mentioned this to her. When my father came to my mother, she said: My son sneezed and you did not respond, but when Umm Kulthum sneezed, you responded to her. He said: Yes, your son sneezed and did not say“Alhamdulillah,”so I did not respond, and this woman sneezed and said“Alhamdulillah,”so I responded to her. The Noble Prophet (peace and blessings be upon him) said: When any of you sneezes and says“Alhamdulillah,”then respond to him, and if he does not say“Alhamdulillah,”then do not respond. She said: Then you did well, you did very well.