(97) باب مَا جَاءَ فِي التَّثَاؤُبِ
Abu Sa'id al-Khudri reported the Messenger of Allah (May peace be upon him) as saying:
When one of you yawns, he should hold his hand over his mouth, for the devil enters. (RU)
Reference (RU): Sunan Abi Dawud 5026 (RU)
In-book reference (RU): Book 43, Hadith 254 (RU)
English translation (RU): Book 42, Hadith 5008 (RU)