We know that if a man has relations with a non-Jewess, the halacha is A zealot may kill him in the act (Sanhedrin 82a). Both R' Schneersohn (the last one -- in Sichos) and R' Tzadok haCohen miLublin ...
(Not to be confused with this question) How can one explain Matzah to a curious colleague in under 18 minutes? So far I have been asked: Why does it need to be extra watched? (I've shown her Sh. ...