Answer:
Amos was a simple man who raised sheep, and 'nipped figs' for a living (Amos 7:14), when God made him a prophet in the 9th century BCE, to warn the nations that were acting wickedly, to stop their bad ways or be destroyed. Amos bravely prophesied to the idolatrous 10-tribe kingdom of Israel in the north which was condemned for turning to false gods, building their "houses of ivory" while cheating the poor(Amos 3:15; 5:11, 12; 6:4-7) . He was sent to Judah for 'rejecting the law of God' (Amos 2:4), and to enemy nations Philistia, Tyre , Edom, Ammon, Moab, to warn them that they would be destroyed for their wicked acts.
God also had Amos prophesy that those who DID turn away from such things and repent, would be shown mercy.(Amos 5:4,6,14)
Amos was a prophet during the rule of Uzziah, king of Judah, during the rule of Jeroboam II, son of Joash, king of Israel and during the 'Great Earthquake', which was SO big that it was still spoken about 300 years later (Zechariah 14:5). When Amos finished his important assignment prophesying to the nations that had turned away from God, he came home to Judah and wrote the prophecies down in his Bible book of "Amos".