As when fire kindles brushwood and the fire causes water to boil: These two parallel lines compare the shaking mountains to water boiling in a pot on a fire. It is unclear how the they are alike. Good News Translation adds the verb “tremble” to clarify the point of comparison. Since this simile interrupts the flow of thought in verses 1-2, Revised Standard Version and New Revised Standard Version place long dashes around it. Good News Translation makes it a separate sentence and repeats the verb “Come” to resume the flow of thought from the previous verse. For these two lines the Septuagint has “as wax is melted by a fire and fire consumes the enemies.” This rendering suggests that the Hebrew text was uncertain long ago, but there is no other textual evidence that casts doubt on Masoretic Text, so translators should retain it. The Hebrew word translated brushwood (New International Version “twigs”) appears only here in the Old Testament, so its meaning is not absolutely certain. The rendering brushwood depends entirely on the context of fire for its meaning. Good News Translation avoids the term.

To make thy name known to thy adversaries: In Hebrew this line begins with an infinitive to indicate that this is the purpose for which the people ask God to come down. They want him to reveal his powerful reputation (name) to his enemies as their Redeemer (see 63.16). His adversaries are the same as Judah’s enemies. They would include the Edomites (63.1) as well as those who destroyed the Temple (63.18).

And that the nations might tremble at thy presence: This line may be understood as a second purpose of God’s coming (so Revised Standard Version). However, in terms of Hebrew grammar it is an independent statement, indicating that the nations would tremble before God (so New Jerusalem Bible; see also the first example below). Alternatively, it may be a plea that is parallel to the call that the mountains quake at God’s presence (see verse 1). If so, it may be rendered “Let the nations tremble before you.” Good News Translation and New International Version regard the verb rendered tremble as a causative verb form, but the Hebrew grammar does not support this.

For the translation of this verse consider the following examples:

• … —just as when kindling [or, brushwood] is set alight,
and the fire makes water boil—
to make your reputation known to your enemies.
Then the nations would tremble in your presence.

• … (like kindling set on fire,
and the fire boils the water),
in order to make your enemies aware of your reputation,
so that the [foreign] nations might tremble before you.

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 .