After God promises to punish Egypt, he promises to punish the Philistines, whose people were very advanced, possessing the ability to forge iron. God will punish them for the taking of the Ark of the Covenant, many, many years ago. Moab will also be punished for pride. In all of these cases, the true God is attacking the false gods. It is worthy of note that the language here echoes Numbers 21:27ff.