A thesis statement is a device used in essays and papers (usually appearing as a single sentence at the end of the first paragraph of your paper) that tells the reader what your paper is about. It can confront the reader with a claim that you'll persuade them to agree with (which is later backed up in the body of the essay with textual evidence and examples) while also providing somewhat of an outline to the paper.
The essay's prompt typically serves as a jumping-off point for your thesis statement. If the prompt is a question, you can directly answer the question and provide a brief statement on why you're answering it that way.
For example, let's say I was confronted with the following topic:
Was Bilbo still a coward at the end of The Hobbit? Give examples from the journey to back up your answer.
My thesis statement at the end of the first paragraph may look something like this:
Bilbo's encounters with the trolls, the goblins, and Gollum show how, along the journey, he transformed from a coward into a brave hobbit.
The thesis statement answers the question while providing an outline of the points I'll be talking about. The body paragraphs of the essay will then elaborate on those examples and explain how they prove Bilbo grew from a coward to someone brave.
Additionally, we can consider Edwards's use of literary devices and techniques to craft a thesis statement for "Sinners in the Hands of an Angry God." Edwards's sermon is designed to appeal to and persuade sinners, telling them about Hell, comparing the wrath of God to great waters, and saying:
The floods of God’s vengeance have been withheld; but your guilt in the mean time is constantly increasing, and you are every day treasuring up more wrath; the waters are constantly rising, and waxing more and more mighty; and there is nothing but the mere pleasure of God, that holds the waters back, that are unwilling to be stopped, and press hard to go forward.
This quote is an example of the language Edwards uses throughout his sermon as a way to intimidate the sinners (and subsequently the readers). We see other examples throughout the sermon, like when Edwards writes that God will inflict wrath without pity, that He will hold sinners over a pit of hell. This mix of intimidation and fear is even more evident when he writes that you "hang by a slender thread, with the flames of divine wrath flashing about," ready to break the thread.
Intimidation isn't the only tactic or device he uses. A good example prompt for this could be as follows:
What literary devices and techniques does Edwards use to persuade the reader and how does he use them? Provide textual evidence.
Throughout the sermon, we see a tonal shift, a shift in point of view, intimidating language, and so on. An example thesis statement could be as follows:
Language, tone, and point of view are used throughout Edwards's sermon to convey the life of a sinner and ultimately persuade sinners to follow God.
There are examples of these throughout the sermon, directly up until the concluding sentence when Edwards states "that every tree which brings not forth good fruit, may be hewn down and cast into the fire." The strong language at the end leaves a heavy feeling in the reader, and likely the sinner, and would act as a final persuading note. Strong language like that can be found throughout the piece and used as textual evidence and explained in the context of the thesis statement.