Amos 1:7

So I will send a fire upon the wall of Gaza,
   and it shall devour her strongholds.

For this sin, the Philistine cities would be completely annihilated—buildings, king, and people. God would turn His hand against them till the last of the Philistines was dead. This judgment was partially fulfilled in the subjugation of the Philistines to the Assyrians later in the eighth century b.c., and more completely during the Maccabean period (168-134 b.c.). Sovereign Lord (’ăḏōnāy Yahweh) occurs 19 times in Amos, but only 5 other times in all the Minor Prophets (Obad. 1; Micah 1:2; Hab. 3:19; Zeph. 1:7; Zech. 9:14). That title stresses both His lordship and His covenant relationship with His people.

fire—that is, the flame of war (Nu 21:28; Is 26:11). Hezekiah fulfilled the prophecy, smiting the Philistines unto Gaza (2Ki 18:8). Foretold also by Is 14:29, 31. First-person verbs (cf. 1:5) describe the direct action of God against Gaza, Ashdod, Ashkelon, and Ekron (vv. 7–8). “Fire upon the walls of Gaza” suggests a military attack under the Lord’s direction. The “fortresses” of Gaza would succumb to the consuming (ʾākĕlâ, “devour,” “eat”) fire of God. The fire would gobble up Gaza’s defenses. Each guilty city is to have its own special punishment, though probably the calamity of each is common to all. Gaza was conquered by Sennacherib when he invaded Judæa in the time of Hezekiah, by Pharaoh-Necho (Jer. 47:1), and by Alexander the Great, who spent more than two months in its siege (Josephus, ‘Ant.,’ xi. 8, 4; Arrian., ii. 27; see note on Zeph. 2:4).