Al-Adab Al-Mufrad, Hadith 920 ⓘ
Ibn 'Abbas said, "When one of you sneezes and says, 'Praise be to Allah,' the angel says, 'The Lord of the Worlds.' When you say, 'The Lord of the Worlds,' the angel says, 'May Allah have mercy on you.'"
حَدَّثَنَا مُوسَى، عَنْ أَبِي عَوَانَةَ، عَنْ عَطَاءٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ قَالَ: إِذَا عَطَسَ أَحَدُكُمْ فَقَالَ: الْحَمْدُ لِلَّهِ، قَالَ الْمَلَكُ: رَبَّ الْعَالَمِينَ، فَإِذَا قَالَ: رَبَّ الْعَالَمِينَ، قَالَ الْمَلَكُ: يَرْحَمُكَ اللَّهُ.
also referenced under: Book 40, Hadith 920 (In-Book) & Book 40, Hadith 920 (English)