The appeal to fear from Jonathan Edwards is an address meant to engage the emotions of the listeners enough to shake them into being convinced of the repercussions of their sins. With the use of Biblical allusions, Edwards gives impact to his words and furthers his credibility.
Revivalist preachers, such as Edwards, a fire-and-brimstone preacher, sought not only to address the minds of the congregation, but also to engage their emotions so as to convince them of the seriousness of their sins and the omnipotence of God, and, by means of frightening images, activate them to seek salvation from punishment as well as understand that their lives are pre-determined. In order to convince his audience that they were in a very precarious state, Edwards compared humanity to a spider and a serpent. In his comparison of man to the spider Edwards told his listeners that they may think that they are alive and well because of measures which they themselves have taken; however, the truth is that they are only alive because of the will of God.
...if God should withdraw His hand, they would avail no more to keep you from falling than the thin air to hold up a person that is suspended in it.
Further, Edwards tells all that are not born again and made new through their faith are in "the hands of an angry God" and if He withdraws His hand, the floodgates would open to the fierceness of God. Further, Edwards employs other images that strike fear into the congregation such as the person's being held over the fiery furnace of God..