He really leaves no options here. EIther get with us and rejoice in heaven, or don't and spend eternity as the "children of the devil." Not only would this be effective imagery for individuals, I imagine a mob mentality would take place, in which people would be coerced into complying with his wishes/demands. Any individual that witnessed this and didn't come back would have been shunned by those that had seen them there and took notice of their absence going forward.

Already living in hell, living in sin, awaiting your eternal fire. Also, perhaps living in the hell of knowing that your fate may be that of whom he speaks. I'm sure a lot of people in the congregation were talking amongst each other and pointing at others at this time, making their guesses as to whom he was referring.

He hates you, he doesn't even want to look at you, but he protects you from falling into hell. Paint a bleak picture and a potential drop into hell, and offer them a way to escape that fate. I would imagine at the time it was very successful in getting the message across.

The imagery here is stunning. I genuinely can imagine the things he is talking about. I can also imagine those that listened to this sermon, and how shocked they must have been at what he was saying. Part of getting his point across is making this all feel believable, and making it something they won't forget.