Amos 1:4 & 5

"'I will send fire upon the house of Hazael that will consume the fortresses of Ben-Hadad. I will break down the gate of Damascus; I will destroy the king who is in the Valley of Aven - and the one who holds the scepter in Beth Eden. The people of Aram will go into exile to Kir.' says the Lord." NIV translation

Because of the way they dealt with the people of Israel, God decrees that He will destroy their king and their capitol. God even says that He is going to use the Assyrians to do this. (Kir was a province of Assyria)

Amos 1:6

"This is what the Lord says: 'For three sins of Gaza, even for four, I will not turn back my wrath. Because she took captive whole communities and sold them to Edom.'" NIV translation

Now, Amos turns to the judgment on Gaza and God could have given a list of charges but He gives a specific reason for the judgment. Gaza was the land of the Philistines who were constantly battling God's people. God's charge against them is simple in that they conquered Israel and sold entire villages into slavery. We know the people of this area as Palestinians today and even now they continue to battle with Israel (God's people).

Amos 1:7 & 8

"'I will send fire upon the walls of Gaza that will consume her fortresses. I will destroy the king of Ashdod and the one who holds the scepter in Ashkelon. I will turn my hand against Ekron, till the last of the Philistines is dead,' says the Sovereign Lord." NIV translation

Because of their treatment of God's people, the judgment is severe and will fall on all of the people and their rulers. Once again, God says that He is going to send fire and that is a reminder that God is purifying the land with this judgment.