For as I consider it in my mind …: The conjunction For may be omitted (so Good News Bible, Contemporary English Version). As I consider it in my mind may be rendered “As I have thought about the meaning of the dream,” “As I understand the dream [or, vision],” or simply “I have been thinking” (Good News Bible)

Alas for those who will be left in those days!: Alas is an expression of woe. Modern English has nothing quite like it, but many translators will be able to find an equivalent. Good News Bible says “how terrible it will be.” In some languages an ideophone will be the correct equivalent. Those who will be left in those days refers to those who survive the troubles at the end of time (see 2 Esd 5.41). This clause may be translated “what a terrible situation it will be for those who are alive in those last days” or “those who are alive in those last days will be in a terrible situation.”

And still more, alas for those who are not left!: Those who are not left refers to those who have died before the end times. Verses 17-18 explain why it will be even worse for them.

Here is a possible model for this verse:

• As I understand it, those who are alive in those last days will be in a terrible situation. But it will be even more terrible for those who have already died by that time.

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.