You shall fall in the open field repeats the threat that Gog and his armies will die. For fall see the previous verse. Here God adds the ominous detail that this will happen in the open field. Some languages say “in the bush.” This phrase carries the implied threat that no one will bury them. In the ancient world it was a very bad fate to remain unburied. Contemporary English Version renders this clause as “your dead bodies left lying in open fields.” Another possible model is “You will lie dead on the ground.”
For I have spoken, says the Lord GOD: This statement stresses that God himself has spoken the words of this prophecy. Says the Lord GOD is the solemn formal declaration that God is speaking. For the Lord GOD, see Ezek 39.1. Revised English Bible translates this whole statement as “for it is I who have spoken. This is the word of the Lord GOD.”
Quoted with permission from Gross, Carl & Stine, Philip C. A Handbook on Ezekiel. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .
