Musnad Ahmad 2542

It was narrated that Ibn 'Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) said: "If one of you says, when he has intercourse with his wife, "In the Name of Allah, O Allah keep us away from the Shaitan and keep the Shaitan away from what You bestow on us (our children),' if a child is born to them, the Shaitan will never be able to harm him.”