The dream interpretation of knife is not good. It is a blade and is used for cutting. If you see someone you know in this same dream with a knife, it can mean you are going to cut away ties with that person.
If you see the other person holding the knife in the dream, it can mean that person wants to harm you. The knife in dream symbol can mean different ways of inflicting damage, which may not be the physical way. Psychological wounds, emotional hurts, and mental stress are all equally harmful.
If you dream of using a knife to defend yourself, it means you know you are being attacked in some way. You carry a knife to defend yourself, or show you are armed, to discourage aggression on you.