Sahih Muslim , Book 42, Hadith 7131 (USC-MSA) ⓘ
The son of Abu Said al-Khudri reported on the authority of his father that Allah's Messenger said: When one of you yawns, he should try to restrain it with cue help of his hand since it is the Satan that enters therein.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ، عَنْ سُهَيْلٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي، سَعِيدٍ عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا تَثَاوَبَ أَحَدُكُمْ فَلْيُمْسِكْ بِيَدِهِ فَإِنَّ الشَّيْطَانَ يَدْخُلُ " .
also referenced under: Book 55, Hadith 75 (In-Book) & Hadith 2995 (Reference)