Edwards was one of the most skilled religious rhetoricians of his time, and in this sermon he demonstrates a particularly able style. The sermon is a jeremiad: it laments the state of society and predicts punishments for human failures. It is also a piece of persuasive writing in which Edwards seeks to convince his listeners to agree with his theological beliefs and undergo the conversion process.
Edwards relies on two versions of ethos: religious authority and his own authoritative voice. He appeals to emotion (pathos) to convince listeners to repent; he does an excellent job of laying out smaller logical conclusions (logos) which build to the point that his audience should convert. His preliminary list of facts about God, hell, and sinners establishes biblical truths, and Bible quotations offer supporting evidence. He contradicts other theological or personal beliefs which the audience might have, and in this way preemptively dismantles arguments that work against his own. His persuasive argument ends with a call to action: if the audience has been convinced by his sermon, they can immediately act upon that conviction by converting today.
He repeatedly uses graphic metaphors to emphasize the spiritual danger his audience is in. As his original audiences would have listened to his sermon (instead of reading it like we do), he makes sure his listeners comprehend his ideas by repeating them several times, and each time he uses a new, terrifying image to drive them home. The metaphors and imagery he uses often come from everyday objects and experiences: insects, fires, and water, for instance.
He also quotes the Bible frequently in his sermon to prove a point he is making—and because his audience would have believed the Bible is the divine word of God, those quotes would have proved to listeners and readers that Edwards’s assertions were correct. Biblical quotation and interpretation are common elements of sermons. In this time period, it was also quite common for sermons to contain lists, possibly because it allowed listeners to keep track of the logical flow of the sermon being preached.
Although contemporary readers might find this sermon longer than necessary, it was actually short compared to many of the sermons given in this time period! Your edition may have additional sermons in it; flip through to see their length, or to see whether they've been excerpted from a larger work, which is often a sign that the full sermon was lengthy. Edwards performs an interesting balancing act here: he addresses many points, finds time to repeat his main assertions and make them more powerful with literary devices, and also keeps his sermon down to a reasonable, listenable length.