The way Edwards concludes his sermon strengthens his overall argument.
Edwards's primary concern is to galvanize people to change their sinful ways. He believes people need to be aware that their transgressions deny them of the chance to fully receive the words of the divine. While the imagery employed might be scary, his primary responsibility is to move people towards believing that they can change their ways through accepting divine teachings.
The conclusion to the sermon emphasizes this possibility for change. Edwards underscores how people need to embrace immediacy in the line "Haste and escape for your lives." This idea reminds people that it is not too late for change. Edwards wants his followers to absorb the idea that the only real transgression is to believe that they cannot be saved. They can make significant changes and "look not behind" as they do it. There is a spiritual summit, or "mountain," that people scale as they seek to be more than what they are. The sooner people embrace the struggle of climbing it, the sooner God's anger will be placated.
Edwards reminds his followers that if they do not embrace this change, they will "be consumed." The conclusion of the sermon helps people accept their own agency. God might be angry, but people can be active agents of spiritual evolution. Edwards's conclusion allows people to believe they can avert spiritual degradation, underscoring the sermon's primary motivation.