that the Messenger of Allah ﷺ said: "Indeed Allah loves sneezing and He dislikes the yawn. So when one of you sneezes and says 'Al-Hamdulillah (All praise is due to Allah),' then it is a right due from every one who hears him to say: 'Yarhamukallah (May Allah have mercy upon you)' As for yawning then when one of you yawns let him suppress it as much as possible and not say: "Hah Hah' for that is only from Ash-Shaitan laughing at him." (Using translation from Tirmidhī 2747)
عَنِ النَّبِيِّ ﷺ قَالَ إِنَّ اللَّهَ تَعَالَى يُحِبُّ الْعُطَاسَ وَيَكْرَهُ التَّثَاؤُبَ فَإِذَا عَطَسَ أَحَدُكُمْ فَقَالَ الْحَمْدُ لِلَّهِ فَحَقَّ عَلَى كُلِّ مَنْ سَمِعَ أَنْ يُشَمِّتَهُ يَقُولُ يَرْحَمُكَ اللَّهُ وَالتَّثَاؤُبُ مِنَ الشَّيْطَانِ فَإِذَا تَثَاءَبَ أَحَدُكُمْ فَلْيَرُدَّهُ مَا اسْتَطَاعَ فَإِنَّ أَحَدَكُمْ إِذَا تَثَاءَبَ فَقَالَ هَاهَا يَضْحَكُ مِنْهُ الشَّيْطَانُ