Why does Edwards claim that nonbelievers are akin to spiders in "Sinners in the Hands of an Angry God"?

". . . and your own care and prudence, and best contrivance, and all your righteousness, would have no more influence to uphold you and keep you out of hell, than a spider's web would have to stop a falling rock."

I. Spiders are considered to be errors of God’s creation.
II. Spiders are powerless should a rock fall on them.
III. Spiders are considered the lowest form of life and thus expendable.

Question

Why does Edwards claim that nonbelievers are akin to spiders in "Sinners in the Hands of an Angry God"?

". . . and your own care and prudence, and best contrivance, and all your righteousness, would have no more influence to uphold you and keep you out of hell, than a spider's web would have to stop a falling rock."

I.	 Spiders are considered to be errors of God’s creation.
II.	 Spiders are powerless should a rock fall on them.
III.	 Spiders are considered the lowest form of life and thus expendable.