Sahih Muslim Book - 53, Hadith - 7488

حَدَّثَنِى زُهَيْرُ بْنُ حَرْبٍ وَمُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ - وَاللَّفْظُ لِزُهَيْرٍ - قَالاَ حَدَّثَنَا الْقَاسِمُ بْنُ مَالِكٍ عَنْ عَاصِمِ بْنِ كُلَيْبٍ عَنْ أَبِى بُرْدَةَ قَالَ دَخَلْتُ عَلَى أَبِى مُوسَى وَهْوَ فِى بَيْتِ بِنْتِ الْفَضْلِ بْنِ عَبَّاسٍ فَعَطَسْتُ فَلَمْ يُشَمِّتْنِى وَعَطَسَتْ فَشَمَّتَهَا فَرَجَعْتُ إِلَى أُمِّى فَأَخْبَرْتُهَا فَلَمَّا جَاءَهَا قَالَتْ عَطَسَ عِنْدَكَ ابْنِى فَلَمْ تُشَمِّتْهُ وَعَطَسَتْ فَشَمَّتَّهَا. فَقَالَ إِنَّ ابْنَكِ عَطَسَ فَلَمْ يَحْمَدِ اللَّهَ فَلَمْ أُشَمِّتْهُ وَعَطَسَتْ فَحَمِدَتِ اللَّهَ فَشَمَّتُّهَا سَمِعْتُ رَسُولَ اللَّهِ -صلى الله عليه وسلم- يَقُولُ « إِذَا عَطَسَ أَحَدُكُمْ فَحَمِدَ اللَّهَ فَشَمِّتُوهُ فَإِنْ لَمْ يَحْمَدِ اللَّهَ فَلاَ تُشَمِّتُوهُ ».

It was narrated that Abu Burdah said: "I entered upon Abu Musa when he was in the house of the daughter of Al-Fadl bin 'Abbas, and I sneezed but he did not say Yarhamuk Allah (may Allah have mercy on you) to me, but she sneezed and he said it to her. I went back to my mother and told her. When he came to her she said: 'My son sneezed in your presence and you did not say Yarhamuk Allah, but she sneezed and you said it to her.' He said: 'Your son sneezed but he did not praise Allah, so I did not say Yarhamuk Allah to him. She sneezed and she did praise Allah, so I said Yarhamuk Allah to her. I heard the Messenger of Allah (s.a.w) say: "When one of you sneezes and praises Allah, then say Yarhamuk Allah (may Allah have mercy on you) to him, but if he does not praise Allah, then do not say it to him.''