Charles Ellicott Commentary Jeremiah 47:4

"because of the day that cometh to destroy all the Philistines, to cut off from Tyre and Sidon every helper that remaineth: for Jehovah will destroy the Philistines, the remnant of the isle of Caphtor." — Jeremiah 47:4 (ASV)

To cut off from Tyre and Sidon. —The two Phoenician cities are coupled with Philistia. Both, as occupying the seaboard of Palestine, were to suffer from Nebuchadnezzar’s invasion. Psalms 83:7 indicates that they were often in alliance. In the “helper that remaineth” we probably have a reference to the foreign mercenaries, especially the Philistines, employed by the two great commercial cities. “Caphtor” has been identified with Crete, Cyprus, Caria, Cappadocia, and the delta of the Nile. On the latter view, the name is held to be connected with Coptic.

Amos 9:7 points to a migration of the people known as Philistines from that region, and there is accordingly a touch of scorn in the way in which Jeremiah speaks of them as the mere “remnant of Caphtor.” In agreement with the first view, we find among David’s mercenaries the Cherethim and Pelethim (2 Samuel 8:18), the two names being probably modifications of Cretans and Philistines. The ethnological table of Genesis 10:14 connects both the Philistines and the Caphtorim with Mizraim or Egypt, and is, so far as it goes, in favor of the Egyptian identification.