Having Relations With One's Wife.
Narrated Ibn `Abbas:
The Prophet (ﷺ) said, "If anyone of you on having sexual relations with his wife said (and he must say it before starting) 'In the name of Allah. O Allah! Protect us from Satan and also protect what you bestow upon us (i.e. the coming offspring) from Satan, and if it is destined that they should have a child then, Satan will never be able to harm that offspring."
The Prophet (ﷺ) said, "If anyone of you on having sexual relations with his wife said (and he must say it before starting) 'In the name of Allah. O Allah! Protect us from Satan and also protect what you bestow upon us (i.e. the coming offspring) from Satan, and if it is destined that they should have a child then, Satan will never be able to harm that offspring."
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ، عَنْ كُرَيْبٍ، عَنِ ابْنِ عَبَّاسٍ، يَبْلُغُ بِهِ النَّبِيَّ صلى الله عليه وسلم قَالَ " لَوْ أَنَّ أَحَدَكُمْ إِذَا أَتَى أَهْلَهُ قَالَ بِسْمِ اللَّهِ اللَّهُمَّ جَنِّبْنَا الشَّيْطَانَ وَجَنِّبِ الشَّيْطَانَ مَا رَزَقْتَنَا. فَقُضِيَ بَيْنَهُمَا وَلَدٌ، لَمْ يَضُرَّهُ ".
Telah menceritakan kepada kami 'Ali bin 'Abdullah berkata, telah menceritakan kepada kami Jarir dari Manshur dari Salim bin Abu Al Ja'd dari Kuraib dari Ibnu 'Abbas dan sampai kepada Nabi shallallahu 'alaihi wasallam, beliau bersabda: "Jika salah seorang dari kalian ingin mendatangi isterinya (untuk bersetubuh), maka hendaklah ia membaca;
ALLAHUMMA JANNIBNASY SYAITHAANA WA JANNIBISY SYAITHAANA MAA RAZAQTANAA
(Ya Allah, jauhkanlah kami dari setan dan jauhkanlah setan dari apa yang Engkau rizkikan (anak) kepada kami).
Jika dikaruniai anak dari hubungan keduanya maka setan tidak akan dapat mencelakakan anak itu."
Sahih al-Bukhari 0141
http://sunnah.com/bukhari/4
http://sunnah.com/bukhari/4