In Hebrew this verse is almost identical to 35.10 (see the comments there). There it referred to God’s people returning from exile and it concluded the words of the prophet, prior to the insertion of the historical chapters 36–39. According to some scholars, its function there in 35.10 as a conclusion is the reason why it has been copied here. While that may well be the case, there is a link between this verse and the previous one with the exodus theme. Verse 9 refers back to the original Exodus, while verse 10 points to the new “Exodus” that is about to take place. Furthermore, since the phrase joy and gladness from verse 3 is included, it seems that the repetition of 35.10 is a deliberate choice of the author.

For this verse translators should repeat the wording of 35.10. See the models there.

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 .