So I will send a fire upon the wall of Gaza, and it shall devour her strongholds.
Now follows a denunciation of punishment, — that God would send a fire on the wall of Gaza, to devour its palaces. And it hence appears that Gaza was a splendid town, and sumptuously built; and for this reason the Prophet speaks of its palaces. He shows, at the same time, that neither strength nor wealth would prevent God from executing the punishment which the Gazites deserved.
What the Lord says here may be explained by what he says Jer 12:14, Thus said the Lord, against all my evil neighbours that touch the inheritance of my people Israel, Behold, I will pluck them out. Damascus was a near neighbour to Israel on the north, Tyre and Gaza on the west, Edom on the south, Ammon and (in the next chapter) Moab on...
Commenting on Amos 1:3-15
But I will send a fire on the wall of Gaza,.... An enemy that shall pull down and destroy the walls of it: this was fulfilled in the times of Uzziah, under whom Amos prophesied; and very likely in a very short time after this prophecy, who went out and warred against the Philistines, and broke down the wall of Gaza, Ch2 26:6; or else...