Amos 1:6

"Thus saith Jehovah: For three transgressions of Gaza, yea, for four, I will not turn away the punishment thereof; because they carried away captive the whole people, to deliver them up to Edom.

Note that the whole of a nation was represented by one of its principal cities, Syria by Damascus, (Amos 1:3), and here, Philistia by Gaza. "It is evident that Gaza is simply regarded as a representative of Philistia,"[25] as proved by the fact that in the announcement of the punishment, some of the other great cities of Philistia are also included, all of them, in fact, standing for the entire nation.

"Carried away the whole people ... to deliver them to Edom ..." The capture and sale of people as slaves was bad enough, but the deliverance of such captives to their worst enemies was an added touch of cruelty.

Amos has in mind such carrying away of captives as occurred in the events recorded in 2 Chronicles 21:16.

"These Philistines captured whole cities and areas of Hebrew people and sold them to Edomites and Phoenicians. The Phoenicians probably sold them, in turn, to the Greeks, as indicated by Joel 3:6."[26]