(13) باب السُّؤَالِ بِأَسْمَاءِ اللَّهِ تَعَالَى، وَالاِسْتِعَاذَةِ بِهَا
Narrated Ibn `Abbas:
Allah's Messenger (ﷺ) said, "If anyone of you, when intending to have a sexual relation (sleep) with his wife, says: Bismillah, Allahumma jannibna ashShaitan, wa Jannib ash-Shaitana ma razaqtana, Satan would never harm that child, should it be ordained that they will have one. (Because of that sleep).
Reference: Sahih al-Bukhari 7396
In-book reference: Book 97, Hadith 25
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 93, Hadith 493