The wrath of God is like great water are dammed
Edwards goes on to extend this comparison and expand upon it. The waters are God’s wrath and the dam that holds back the deluge is God himself. The pressure is constantly building and humans can never know when God will decide to release that press by opening up the dam and allowing His wrath to flow freely.
Your wickedness makes you...heavy as lead.
The simile here is engaged by Edwards to draw a parallel between the lightness of a sacred life versus weight that one carries around by doing wickedness. The heavier a person feels as a result of the wickedness they do, the closer to hell they are being dragged.
The dreadful pit of the glowing flames of the pit of hell.
Edwards very often casts the fires of hell in metaphorical terms rather than using a simile to compare it to fire. In fact, Edwards reference hell as eternally burning that it may not even be entirely metaphorical. He may be describing it literally though, since he has never been there, this would be impossible.
Black clouds of God's wrath.
A sermon on the subject of God’s anger would be expected to refer to His wrath quite often and, indeed, Edwards creates many more similes beside dammed waters to describe it. Calling God’s wrath black clouds “hanging directly your heads, full of the dreadful storm” is, however, one of the rare occasions in which foregoes the “like” or “as” to directly situates wrath as pure metaphor.
Let everyone fly out of Sodom.
This is a final admonition to the congregation as the sermon draws to a close. Sodom here is a metaphor for the condition of living a sinful life. Less a symbol of place than of being, Edward draws upon the Biblical story of the wholesale destruction of everybody in a city as a final horrifying thought to send the parishioners on their way: nobody is safe when there is sin around them.
