The Israelites are deeply complacent.
The first section of this chapter is essentially saying “you better believe the prophets”. It uses a series of analogies that are similar to “where there is smoke there’s fire”, ie the prophets don’t wander about saying “repent”‘ just for the heck of it.
Because the they are close to God, because Israel is gods chosen, they are gods way of giving Israel a chance and a warning that their complacency needs to end.
It seems this is written at a time when Israel was relatively powerful and prosperous, and had expanded into neighbouring countries. But they have assimilated too much, and the oppression and luxury of the neighbours was sapping their spiritual strength. So judgement is coming on their neighbours and on them.
It’s not hard to draw a comparison to gods people today, is we over assimilate into the world. This is an elaboration of the point made in the first two chapters, that God doesn’t speak loudly though anaemic believers.
It’s all very well to gather in our churches and talk about the urgency for the unsaved. But when we are out amount them, how distinctive are we? How saved do we behave?