What does Genesis 14:8 mean?

The previous verses describe the war of the four kings of the east, led by Chedorlaomer, king of Elam, against the city-states and peoples of the land of Canaan. Defeating all in their path, their route took them south along a line east of the Jordan River all of the way to the edge of the southern wilderness before turning back north to defeat Kadesh and the peoples south of the Dead Sea.

Now the four kings come to the Valley of Siddim to do battle against the five kings listed in this verse. Those five kings include the kings of Sodom and Gomorrah. It will be helpful to remember that Abram's nephew Lot had pitched his tents near the city of Sodom, as described in Genesis 13. This puts his family directly in the path of this counter-revolutionary army.