‘Therefore thus says the Lord Yahweh, “As the vine trees among the trees of the forest, which I have given to the fire for fuel, so have I given the inhabitants of Jerusalem, and I will set my face against them. They will go forth from the fire, but the fire will devour them. And you will know that I am Yahweh when I set my face against them. And I will make the land desolate, because they have committed a trespass,” says the Lord Yahweh.'
The reference to Jerusalem is now made clear. They are just fuel for the fire. Their land is to be made desolate because of their sin. And this will be because Yahweh has set His face against them. So even those who go forth from the fire and seemingly escape the judgment, will find that judgment follows them (compare Ezekiel 5:2 - ‘I will draw out a sword after them').
‘And you will know that I am Yahweh when I set my face against them.' What happens to them will make all recognise Who and What Yahweh is.