The thesis, or central argument, of this fire-and-brimstone sermon of Jonathan Edwards is that those who have not accepted Jesus Christ as their Saviour dwell on the brink of damnation and the eternal horrors of Hell. Edwards paints a picture of the insecure nature of man's existence, arguing that those who have not had a transforming religious experience (so that they are "born again") could be "dropped" by God into Hell at any moment. Thus, in response to the precarious position occupied by man, Edwards argues, we should throw ourselves upon the grace and mercy of God to be spared this fate.
It is clear that fear is one of the main tactics that Edwards uses in this sermon. He is trying to make his listeners so afraid of the thought of eternity in hell that they will act now to be "born again." Note how this fear is introduced:
So that, thus it is that natural men are held in the hand of God, over the pit of hell; they have deserved the fiery pit and are already sentenced to it; and God is dreadfully provoked, His anger is as great toward them as to those that are actually suffering the executions of the fierceness of His wrath in hell, and they have done nothing in the least to appease or abate that anger... the devil is waiting for them, hell is gaping for them, the flames gather and flash before them...
Thus Edwards establishes his central argument. Without trusting in God and being "born again," we have only one fate to look forward to, and this fate he spends much time and uses many figures of speech to paint in all its horror.