What does the old man mean by putting the knife under the bed?

I heard that some people put things like knives or scissors under their pillows, as if to ward off evil spirits. It is aimed at people who often have nightmares, but people should pay attention to safety when putting these sharp weapons, so as not to hurt themselves and their families. This is just what people often say. True feng shui should be people-oriented. You can refer to Moya Holographic Geomantic Network. It is good for you to know more.