God's Wrath, God's Grace (Situational Irony)
There’s a sort of terrifying irony in the fact that the same being, God, whose wrath is responsible for dooming you to eternal damnation is also, at the same time, the only thing saving you from that same damnation. The irony of this situation, driven home again and again by Edwards, serves to reinforce the sense in the listener of the precariousness of their situation.
The Tale of the Israelites (Situational Irony)
Edwards, by beginning his sermon with a story about the Israelites, effectively encourages his listeners to believe they’re in for a tale about the wickedness of people far removed from themselves. Thus, in an instance of situational irony, he “tricks” them, so to speak, into enacting the very foolish self-assured confidence in their own safety and righteousness for which he will scold them later on.