From what I have read in my commentary,
here is a brief summary of the message of Amos.
The book opens with this humble shepherd watching his sheep. God then gives him a vision of what was about to happen to the nation of Israel. God condemned all the nations who have sinned against him and harmed his people. Beginning with Aram, he moved quickly through Philistia, Tyre, Edom, Ammon, and Moab. All were condemned, and we can almost hear the Israelites shouting, "Amen, they deserved it!" Then, even Judah, Amos's homeland, was included in God's denunciaiton. How Amos's listeners must have enjoyed hearing those words! Suddenly, however, Amos turned to the people of Israel and pronounced God's judgment on them!!
As we read through the book of Amos, let's put ourselves in the place of those Israelites and listen to God's message. Have we grown complacent? Have other concerns taken God's place in our lives? Do we ignore those in need or oppress the poor? Think of Amos, who faithfully is doing what God calls him to do. We, too, can be God's person. Listen for his clear call and do what he says, wherever it leads.