Pesachim 8A (link) says: R. Elazar taught that harm will not befall a Shali'ach (someone on the way to do a) Mitzvah! That is a short excerpt from a discussion about being protected when doing a ...
I had asked what is the source for the segulah of having relations twice in order to have a boy. I first asked this in order to obtain a source to better ask this question. The Gemorah says in Niddah ...