When a guest, eats the food and drinks the drink off a host’s table, beneath the host’s roof, the guest right is invoked. When invoked, neither the guest can harm his host nor the host harm his guest for the length of the guest’s stay. For either to do so would be to break a sacred covenant that is believed to invoke the wrath of the gods both old and new.
countdown to season 3→ 1.09 Baelor "You think my life is some precious thing to me? That I would trade my honor for a few more years of what? You grew up with actors… you learned their craft and you learnt it well, but I grew up with soldiers. I learned how to die a long time ago.”