From Sahih Bukhari (Hadith 141):
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
Reference: Bukhari 141