According to the first verse of his book, Amos lived during the reigns of Uzziah (= Azariah in 2 Kgs 15), king of Judah from 791 to 734 BCE and Jeroboam II, king of Israel from c. 786 to 746 BCE.

After the introduction (Amos 1 and 2), the book can be divided into the sermons (ch. 3–6) and the five visions (7: 1–9: 7), followed by the Promise (9: 8–15). It is particularly important for the rejection of the view that for each nation there was its own god—Yahweh being that of Israel, whose writ did not extend beyond the borders of the two kingdoms. On the contrary, the theme of Amos is that Yahweh is the universal God with moral demands on every nation (e.g. Amos 1: 5) whose crimes are denounced because they are intrinsically wicked, not necessarily because they have injured Israel. Doubtless there was the special relationship between Yahweh and Israel, but the nation was warned that it would not be preserved by mere rituals. The priest Amaziah did his utmost to silence this unwelcome message at Bethel (7: 12), but Amos persisted. At any time the contract might be broken (Amos 5: 18); and yet a hope remained of ultimate restoration (9: 11–15); and even if this conclusion was added by a Deuteronomist editor at a later date (621 BCE), it is how the book has been read within the context of the Bible as a whole by both Jews and Christians, and as such it is not necessarily to be dismissed on the grounds of being inconsistent with the message of Amos in 750 BCE or treated as an unauthentic appendix. The book of Amos is quoted by Stephen (Acts 7: 42) and by James (Acts 15: 16–18), and in modern times has been much valued for its forthright appeal for social justice, and the famous 5: 24 hints at a universally understood moral code.