Amos continues God's rant against everyone that has done him wrong. Get it all out LORD, you don't want to have a stroke.
Amos does give us a theme to make the reading easier.
Thus saith the LORD; For three transgressions of <insert evil people here>, and for four, I will not turn away the punishment thereof; because <fill in transgression here>...
This one line is the smoking gun I've been looking for.
As people left to start out on their own, why didn't God smite the hell out of them as a lesson?
I truly would love to hear an answer.
Chapter 4 just highlights how clueless God is when he wonders why his people no longer worship him, even after he's starved them, killed their young men and brought drought and floods to the land.
Still, Amos/God continue spewing the same doom and gloom as the others have.
The last part of the book gives us Amos' origin story. He is warned not to go into the prophet biz but God insists.
God uses props to help Amos understand. A plumbline and basket of fruit.
He also will cause a famine of himself.
We end the book with God again promising to destroy all but a few of his special people.
He then makes a promise, that Israel "shall no more be pulled up out of their land which I have given them".
Only took him 2500 years to keep that promise and even now, Israel is under constant threat from it's neighbors.