This verse is a problematic one. Its difficult grammar and the different texts found in the ancient versions have even led some commentators to abandon all attempts to reconstruct the original text. Despite these difficulties the general thrust of the verse is clear (see Good News Translation), so standard translations do not vary widely.

One of the difficulties involves the Hebrew root gml (meaning “to pay back”), which is rendered once as deeds and twice as requital. Requital in English is roughly synonymous with “vengeance/repayment.” Another difficulty is the occurrence twice of the unusual Hebrew expression keʿal, which is rendered According to … so…. But Dead Sea Scrolls contains all these expressions, so there is no reason to suggest any emendation.

According to their deeds, so will he repay: There are two ways to interpret this line: either Yahweh will punish his enemies in a way that is appropriate to the sins they have committed, or he will deal with them in the same way that they themselves dealt with others. The first interpretation seems to be the sense that emerges from most versions, but the second one illustrates a principle that is important in the Old Testament—justice is accomplished when those doing something wrong are punished in the same way they treated others. So According to their deeds may mean in the same way they acted or on the basis of the way they acted. Translators may follow either sense. The pronoun their refers to God’s adversaries/enemies mentioned in the next line. He will repay means he will pay them back for what they have done. Some languages may require an object for the verb repay. If so, see the second example below.

Wrath to his adversaries, requital to his enemies: These two synonymous parallel statements express God’s “repayment.” God’s wrath refers not just to his angry feelings, but also to his punitive action. God will punish these people in anger for what they have done to others. God’s adversaries/enemies are all those who act unjustly, whether they are people in Judah or foreigners. As we noted above, requital means “repayment” or “vengeance.”

To the coastlands he will render requital: This line is not in Dead Sea Scrolls; Revised English Bible omits it. Some commentators suggest that it is a later addition by an editor to explain that God’s enemies here are not from among the people of Judah, but they are from the coastlands, that is, they are foreigners. We recommend keeping this line since it is in Masoretic Text and Hebrew Old Testament Text Project firmly supports it. The line means the LORD will punish foreigners according to what they have done. For the Hebrew word rendered coastlands, see the comments on 11.11 and 41.1. Here it generally refers to foreign nations, especially those that are distant. Good News Translation says “those who live in distant lands.” Render translates the same Hebrew verb rendered repay in the first line. For this line New International Version says “he will repay the islands their due,” and New Jerusalem Bible is similar with “to the coasts and islands he will repay their due.”

For the translation of this verse consider the following examples:

• On the basis of what they have done, so the LORD will repay;
his anger will be seen against those who oppose him,
his payback against his enemies;
he will repay those in the coastlands.

• Yahweh will repay people according to what they have done;
those who oppose him will experience his anger,
his enemies will be punished,
even those living far away will be punished.

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 .