Referencing is at the core of any kind of scholarly (or academic) writing. It might help if you envision your academic writing as a dialogue with somebody else.
In an ordinary conversation you would usually be challenged. The person with whom you were discussing would say: “how do you know that,” “where did you hear that,” “really,” or simply “get out of here, you don’t know what you are talking about.” In written communication your reader doesn’t have the possibility of saying this directly to you. This, however, doesn’t mean that she/he doesn’t do so while reading. In your writing you want to give the answers to the imagined challenging questions by footnoting sections where you imagine your reader would ask any of the questions above.
Imagine referencing like a map of where you found your information and how you constructed the knowledge that you present in the essay. Trust is absolutely necessary in successful communication and by referencing your essay you tell your reader that you feel confident enough to have her/him check your sources. It makes your reader believe in you and by extension the soundness of your argument.
What do I need to reference?
A reference is, at minimum, required when you: