What does Genesis 14:15 mean?

After learning that Lot had been taken captive by the forces of Chedorlaomer and the kings from the east, Abram immediately gathered 318 of his most reliable trained men and began his pursuit of the departing armies. Armies of the ancient world were significantly smaller than those of modern times. However, the combined forces of four kings, even after a campaign, would have been many, many times the size of Abram's army.

Abram apparently caught up to them at Dan, in the northern reaches of the land of Canaan. Here, strategy helps Abram and his men overcome the numbers of their enemy. Abram divides his men and attacks by night, defeating the enemy. They continue to chase the retreating eastern soldiers down as they flee farther north toward the ancient city of Damascus. This is a strong contrast to Chederlaomer's previous battle, which saw five kings literally fleeing from him in defeat (Genesis 14:10–11).

What a victory! The four kings from the east had defeated multiple kings, city-states, and people groups in Canaan with apparent ease, never suffering any loss that we know of. Clearly, they were a strong fighting force. Still, with God's help, Abram and his personal army of 318 men and three Amorite allies defeats them in a single night.

God had promised to bless Abram, as well as to bless all who blessed him and curse all who dishonored him. The mighty Chedorlaomer had dishonored Abram by taking his nephew (Genesis 14:12), and now God keeps His promise once again.