The sword has been sent upon you: Compare Ezek 21.8-11. Here the word sword is an image for “war” (Good News Bible, Contemporary English Version; see the comments on 1 Esd 1.53). Good News Bible refers to God in the first person here, but in our opinion this whole section will be better expressed in the third person for God (so Contemporary English Version), the performer of the actions. This clause may be rendered “God has declared war on you” or “God is sending war on all of you [or, the four of you].”

And who is there to turn it back?: This question is rhetorical, so it may be rendered as a strong statement, for example, “and no one can stop it” (Good News Bible, Contemporary English Version) or “and no one can prevent it now.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Esdras. (UBS Helps for Translators). Miami: UBS, 2019. For this and other handbooks for translators see here.