Sahih al-Bukhari, Book 59, Hadith 81 (In-Book) ⓘ
Narrated Ibn `Abbas: The Prophet said, "If anyone of you, when having sexual relation with his wife, say: 'In the name of Allah. O Allah! Protect us from Satan and prevent Satan from approaching our offspring you are going to give us,' and if he begets a child (as a result of that relation) Satan will not harm it."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا هَمَّامٌ، عَنْ مَنْصُورٍ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ، عَنْ كُرَيْبٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " أَمَا إِنَّ أَحَدَكُمْ إِذَا أَتَى أَهْلَهُ وَقَالَ بِسْمِ اللَّهِ اللَّهُمَّ جَنِّبْنَا الشَّيْطَانَ، وَجَنِّبِ الشَّيْطَانَ مَا رَزَقْتَنَا. فَرُزِقَا وَلَدًا، لَمْ يَضُرُّهُ الشَّيْطَانُ " .
also referenced under: Hadith 3271 (DarusSalam) & Volume 4, Book 54, Hadith 493 (USC-MSA)