Judah’s defeat is expressed in mathematical terms here. Only a few Assyrian soldiers will cause the whole army of Judah to flee, despite their brave claims in the previous verse. Only a few soldiers of Judah will remain like a single flagpole on a hill. Of course, this is a hyperbole that pictures complete devastation. The use of numbers is frequent in the Wisdom literature; see, for example, Job 5.19 and Pro 30.18-31. Translators need to consider whether their readers might take the numbers literally, rather than see their figurative meaning. If there is doubt, the numbers should be adjusted to bring out their underlying meaning; for example, one may be rendered as “only one,” and five as “merely five.”

A thousand shall flee at the threat of one is literally “One thousand from before the threat of one.” The Hebrew text lacks the verb flee. However, the next line has this verb, so it is appropriate to supply it here as well. New Jerusalem Bible emends Masoretic Text to read “A thousand will quake at the threat of one,” but Hebrew Old Testament Text Project firmly rejects this. The Hebrew noun translated threat comes from a root meaning “rebuke.” New Jewish Publication Society’s Tanakh renders it “shout,” but it is better to say “threat” (New Revised Standard Version, New International Version, New Jerusalem Bible, New American Bible) or “challenge” (Revised English Bible).

At the threat of five you shall flee: This line is parallel with the previous one. Although it uses a different mathematical ratio, the point is the same: a small number of enemy challengers will cause many soldiers of Judah to flee.

Till you are left like a flagstaff on the top of a mountain, like a signal on a hill: These three lines use two similes to illustrate the complete defeat of Judah by Assyria. There will be so few soldiers of Judah left that they will be like an isolated flagpole on the top of a hill. Till you are left like … may be rendered “until all that is left of you is as lonely as a…” or “until all that remains of you is like….” Like a flagstaff on the top of a mountain is synonymous with like a signal on hill, since the Hebrew words for flagstaff and signal both refer to a flagpole here (see the comments on signal at 5.26; see also 11.10, where the same Hebrew word is translated “ensign”). Good News Translation combines these two lines, which may be helpful for other languages.

For the translation of this verse consider the following examples:

• A thousand of you will flee from the challenge of just one,
you all will flee at the challenge of just five;
in the end all that will remain of you will be
like a lonely flagpole on a mountaintop,
like a signal on a hill.

• Just one challenger will cause a thousand of you to flee,
five challengers will put all of you to flight,
until those of you who are left will be
like a single flagpole standing on a mountaintop.
You will be like a lonely signal [or, pole] on a hill.

Quoted with permission from Ogden, Graham S. and Sterk, Jan. A Handbook on Isaiah. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here .