The Book of Zuhd and Softening of Hearts
55/9. Chapter:
Saying: "May Allah Have Mercy On You" To One Who Sneezes, And Yawning Is Disliked
Sahih Muslim
حَدَّثَنِي أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنِ ابْنِ أَبِي سَعِيدٍ الْخُدْرِيِّ، عَنْ أَبِيهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا تَثَاوَبَ أَحَدُكُمْ فِي الصَّلاَةِ فَلْيَكْظِمْ مَا اسْتَطَاعَ فَإِنَّ الشَّيْطَانَ يَدْخُلُ " .
The son of Abu Said al-Khudri reported on the authority of his father that Allah's Messenger (ﷺ) said. When one of you yawns while engaged in prayer, he should try to restrain so far as it lies in his power, since it is the Satan that enter therein.
Reference : Sahih Muslim 2995cIn-book reference : Book 55, Hadith 76USC-MSA web (English) reference : Book 42, Hadith 7132