Following are a number of back-translations as well as a sample translation for translators of Isaiah 4:25:

• English: “That is why Yahweh is extremely angry with his people;
  it is as though his hand is raised and he is ready to smash them.
  When he does that, the mountains will shake,
  and the corpses of people will be scattered in the streets like manure.
  But even when that happens, Yahweh will still be very angry;
  he will be ready to punish his people again.” (Source: Translation for Translators)