there are a few ways to explain what fear is: molecular-biologic, linguistic-psychologic, and the esoteric:

• the parasites thrive on fear molecules; the ultimate favorite appears to be adren0ch0me, the type procured by most demon-infested humans & beasts; other stimulants and their metabolites... like the ordinary adrenaline - suffice for the average parasites-in-flesh; example: one goes to a parasite-infested pit such as a commercial hospital and comes back home disturbed, anxious, and perhaps itchy; gotchu again!
• the recommendation "have no fear" can have different effects based on the framing: some people might start envisioning what fear is once they hear the word... perhaps it is triggering; for others, defining fear makes the word lose its potency; it is helpful to instead focus on what fear is not and keep envisioning those conditions; defining desired outcomes in words for something like "freedom" is typically not effective; u have to envision it, using imagination;
• esoteric perspective: evil/feardom/carelessness is the contracting, degenerating force of involution, whereas love/freedom/care is the expanding, generating force of evolution; in a state of fear - things die; in a state of love - things live;

quick tip for avoiding contracting parasitosis in public: