speaking for myself, I can take prophets for granted, because I just open my bible and there they are.
But, the “context” is not just the literary context in Amos, which is very appropriate of course to understand this verse. But, as the other posters have pointed out, this is a very harrowing time – if I understand the situation – that the Assyrian empire is massing itself nearby to overthrow Israel, in its quest to conquer everybody.
What I was reading today is that Assyria not merely conquered, but they broke up the conquered nations by herding people in and out, to mess with their minds – to move the conquered to new, foreign places, and, here, threatening to force migration into the Holy Land to take the place of the Israelites – for the devastating historical, political, and social consequences that this would have.
And, working through the prophets, God was working “outside the system” of Levites and temple priests and other institutional people like that.
I’m way out of my league on this, I guess, but these prophets may have been on the level of a Rush Limbaugh (in notoriety) but like Rush, outside the system. (I don’t listen to RL; I’m just using him as an example).