(54) باب مَا يَقُولُ إِذَا أَتَى أَهْلَهُ
Narrated Ibn `Abbas:
The Prophet (ﷺ) said, "If anyone of you, when intending to have a sexual intercourse with his wife, says: 'Bismillah, Allahumma jannibna-sh-shaitan, wa jannibi-sh-shaitan ma razaqtana,' and if the couple are destined to have a child (out of that very sexual relation), then Satan will never be able to harm that child."
Reference: Sahih al-Bukhari 6388
In-book reference: Book 80, Hadith 83
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 75, Hadith 397