The earliest prophetic book, Amos sheds an additional, even if small, personal light on a cataclysm drowned out by the distant past.
The prophet gives the start of his mission as two years before the Great Earthquake - c.762 BC - and continued until the 740's BC. He originates from Judah. While there are earlier prophets recorded to have written (1 Chron. 29:29), these seem to have been secular, court officials. Thus Amos is the earliest prophet known to write down his prophecies. It's very possible that he was thrown out of Bethel (7:10-13), and therefore wrote down his oracles from Judah - an action that later prophets imitated. His trade actually identifies him as a man of means, who could've known (or learned) how to read and write: perhaps why he was considered a threat by Amaziah the priest (7:10ff).
Some chop up the book into several stages of redaction. Robert B. Coote sees three in particular: Stage A (Amos himself), B (mid-7th century BC redactor), and C (late-6th century redactor). Stage A consists of: 2:6b-8, 13-16; 3:9-11, 12-13; 4:1-3 (without "Harmon" at end of v.3); 5:1-2, 11-12, 16-17, 18-20; 6:1-7 (sans "Zion" in v.1 and without David in v.5), 6:8a, 11; 8:4-7, 9-10; 9:1b-4a, with additional possible words or phrases in the rest, though these have lost their "Amos character" sufficiently. He considers these to be marked by a prediction of inescapable doom for the Samarian elite, with no hope of salvation for any remnant. Amos is a staunch defender of the poor, whom he equates with the righteous. Stage B is a mid-7th century author who wanted to warn his native Judah from the lesson of Amos, and offers an incorrect choice that can be fixed, but is still wanting. In other words, he has hope. Stage C is a redactor (mainly verses 1:1-12 and 9:7-15). He writes near the end of the Exile in the late 6th century BC, and has a hopeful outlook.
There are numerous problems with Coote's hypothesis in particular. He admits there's a lot of "necessarily" circular reasoning in his criteria. [Coote, 15] He claims that none of the elite/well-off will escape because they oppress the poor, yet...Amos is not one of the poor as he notes! [Coote, 43] This completely contradicts two of the four reasons (#2-3) he gives why Amos couldn't have believed in a "remnant" [Coote, 45] that the specific references means zero rich Samarians would be convinced and that they would simply latch onto the hope of being saved - clearly Amos' remnant would be saved by not doing the very things he condemns, so Coote's suggestion is like a criminal believing he'll be acquitted of a crime despite the evidence just because...other defendands in the past have been acquitted (against whom there was insufficient evidence).
His other two objections are that a remnant "violates most of the characteristics of the A-stage oracles", which begs the question especially as we noted he admitted it was mostly circular reasoning. His last reason depends on this because for him Amos considers only the poor to be righteous (2:6; 5:12). Yet this reason is dependent on the former. At any rate, he clearly didn't see that Amos 3:12 expects that some of the elite will physically escape (despite the threats in 9:1-4), but this escape will be meaningless with respect to their former lives and possessions.
Some of his divisions between Stage A and B are equally mysterious. According to him, Stage B didn't really tamper with Stage A's material, and may contain a word or line from the original Amos here and there. Yet why exactly are 6:8b-10, 17, 7:17, or 9:4b rejected when they predict inescapable doom for the Samarian elite and don't go against any of his other criteria (e.g. no specific places besides Samaria; yet allows 3:9)? Furthermore, he admits that oracles such as those about the fall of Aram must necessarily come...before the fall of Aram (or at least not too much after it), yet assigns those to Stage B. [Coote, 67] He rejects them on the basis that Amos "did not require such a long hearing or the making of connections over such an extended amount of material to make his points." [ibid.] But the Damascus oracle relevant to Aram is only 1:3-5. I'm guessing Coote forgets that this is a book that collected these short oracles, a criteria that he imposes for little reason other than his decision that the historical Amos must've delivered everything absolutely short and snappy. For this reason he considers the oracles after 5:16-18 to be Stage B's addition because they "ruin" the pun in 5:16. But it doesn't occur to him that a pun becomes "ruined" once it's revealed; Amos can't deliver any more prophecies after this unless he keeps coming up with puns? At any rate, the groupings are literary, a point Coote seems to forget once again, which is especially strange here as he has a separate authentic Amos oracle right after this (Amos 5:18-20).
Either way, it's not just the elite, rich in Samaria (but not Bethel?) that are condemned. Even in his Stage A, subtle, hidden from Coote's observations it seems, there are the hints of a universal northern suffering. In 5:2 all Israel is desolate. In 5:16-17 the farmer and vineyard workers (whom the elites extort - pp.33-34) are also mourning. In 6:7 the elite are the first of the captives. Also perhaps 6:11 - both big and small houses will perish. Amos 2:6b and 5:12 are therefore probably not equating the poor with the righteous automatically, but giving examples of the profaning of justice by the ruling class.
Amos and Prophecy
It's simply strange that a prophet would go from Judah to the northern kingdom and could only condemn a specific class, but only in Samaria, not Bethel, and repentance was pretty much out of the question. This last idea he supposes because the oppressed peasant didn't want to debate an ignorant overlord who could never care, but merely wanted an outcry. [Coote, 43] But Coote himself admits Amos wasn't poor! [ibid.] Amos had to have the same theme for decades? Yet his oracles were written down and remembered so much amidst such versatile authors of that time like Hosea and Isaiah, that not just Editor B, but also Editor C decided to throw their lot in with his authority? [Coote, 23-4] And Editor C did this by basically adding a few verses in the beginning and end, all the while his entire message of hope was diametrically opposed to Stage A, and with a very grim outlook in Stage B, which he didn't touch! Not to mention Coote can't even be certain where Stage C's editor got "all that good poetry", and it's "an unanswerable question" whether it comes from Amos. [Coote, 122] Coote makes his own observation about the futility of prophesy without repentance unanswerable. [Coote, 43] Amos may as well be a Southern agent attempting a popular revolt with this reconstruction.
This is why in reviewing his book, Ziony Zevit writes:
The clear distinction between A and B which turns the prophet Amos into a Samarian doomsayer is unsupported in the text. It is one thing to isolate all of the oracles directed against the rich (of Samaria); it is quite another to claim that these alone are the main extant words of the original prophet. Much of the material assigned by Coote to B and many of the ritual and legal concerns expressed there cannot be dissociated from Amos A on any objective philological, form-critical, or theological grounds. Coote's unstated assumption in this work is reminiscent of the formula which characterized much of prophetic scholarship prior to the 1950s: doom = preexilic; salvation = postexilic. [Zevit, Ziony. Journal of Biblical Literature 102, no. 2 (1983): 309]
In addition, he notes an issue with Stage C (vv.1:3ff):
The distribution of the oracles against the nations between B and C (pp.66-69, 112-15) must be reconsidered in the light of S. M. Paul's study, "Amos 1:3-2:3: A Concatenous Literary Pattern," (JBL 90  397-403). Arguments for the post-exilic theological appropriateness of the oracles against Tyre, Edom, and Judah do not demonstrate their postexilic origin. [Zevit, Ziony. ibid., 309]
In other words, the text of an undated, anti-German newspaper clipping in French could be easily describing a WWI or WWII incident, or it could be from 40-60 years earlier during the Franco-Prussian War.
Amos and Contemporaries
His rejection of "Zion" in 6:1 is based on more of the same reasoning above (too specific and only Stage B was concerned with denouncing Bethel). But seeing that this isn't persuasive, the Judean Amos would have easily been able to redirect worship toward Jerusalem, unlike the northern Hosea, who merely denounces paganism - at the same sites Amos does: Bethel, Gilgal, as well as others. Many older traditions refer to Jerusalem as Zion (2 Sa 5:7; Isaiah 1:8, 27, etc). Isaiah 6:1, 4 also considers Jerusalem as the legitimate center of God, so there's nothing preventing Amos to have said 1:2.
Another qualm for Coote is the places in the book where "Israel" refers to both the north and Judah. Yet, Israel can be a euphemism for all Hebrews (Hosea 12:13), especially for a Southerner.
Historically, there are a few points he mentions. First, Jeroboam II (7:11) didn't die by the sword. But Amos prophecies against the house of Jeroboam (7:9). The objection is simply based on the fact that Amos is prophesying during Jeroboam II's reign, which for Coote is not an option as he has to push him closer to 722 because that's when there was deportation and so on. One probably didn't even need to be a prophet to foresee the doom from Assyria upon rich Israel, and that deportations were standard procedure.
The siege of Tyre is speculated to be the one under Nebuchadnezzar (hence Stage C). But there was a siege of Tyre in 724-720 and Assyria finally took it. Most importantly, the Edomite "backstab" against Israel is supposed to be the one against Judah in the 6th century. Although Amaziah of Judah (early 8th century BC) defeated the Edomites, they were never completely under control (2 Kings 14:7; 2 Chronicles 25:11–12). So the Edomites attacking Israel in the late 8th century BC is plausible - not just the 9th or 6th centuries.
Common language between his A and B stages includes turning justice/righteousness into "wormwood" (5:7; 6:12). Numerous words "might go back to Amos A" (a phrase used frequently), [Coote, 76] including the condemnation of Bethel. [Coote, 96] Imagery of a lion, which he differentiates as A-stage that kills (3:12; 5:19) vs B-stage that roars (3:4, 8). [Coote, 13] Yet he doesn't consider the similar words used ari and aryeh by the supposed different Stages to be like his pun in 5:16 for some reason. Not to mention, the connection that he also notes in aryeh used in Amos 1:2 which is supposed to be from stage C! [Coote, 59-60]
Anyway, similarities between Amos 5:21-25 and Isaiah 1:11-15, as well as Amos 4:7-11 (Is. 9:8-21, particularly vv.13, 21); 5:11, 7:14 (Is. 9:10) shows at the very least a common 8th century tradition. Moreover, Hosea, a northern prophet, criticizes Bethel and Gilgal, so there's no reason to assign this condemnation to Stage B one hundred years later. The common tradition between these two 8th century prophets is seen in the reference to the Samarians as "cows" (Amos 4:1; =stubborn in Hosea 4:16).
But the most damaging clues against this kind of "decomposition" is from language. Although Amos writes in southern (Judean) Hebrew, he shows sign of a northern contact. For example, he makes exactly the kind of puns Coote considers his in 7:7-8 and 8:1-2. [Amos' Puns in the Northern (Israelite) Dialect - TheTorah.com] Not only are they puns in Hebrew, they're puns in the spoken Northern Hebrew. [Wolters, A. 1988. “Wordplay and Dialect in Amos 8:1-2,” Journal of the Evangelical Theological Society 31: 407-10.] Meaning Amos must've delivered these. In fact, Amos 8:1-2 has a very "Amos-like" character given Coote's parameters. The "basket of summer fruit" is identical with the Northern way of saying "basket of end"! But Coote assigns them to Stage-B, long after the north and its relevance was gone.
Coote's book just seems "pleasantly confused". It just doesn't realize how many times it contradicts itself not just with respect to logic and evidence, but from its own assertions. For example, Coote says:
A majority of redaction critics suppose that three kinds of material in the prophetic collections go back directly to the prophet: poetic sayings, first-person reports by the prophet, and third-person reports about the prophet. [Coote, 89]
But goes to eliminate the last two categories because of his own idea of who Amos must've been, and even contradicts this in the beginning of the book when he says that, "These oracles are composed in poetry, a nearly invariable feature of preexilic prophecy and a feature whose significance can hardly be overstressed." [Coote, 17] One has more evidence for multiple redacted stages in Coote's own book, than in Amos.
- Coote, Robert B. Amos Among the Prophets (Fortress Press, 1981)