The law that the Lord had given Israel stipulated that a wrongdoer was to be punished in equal measure to what he had done (Exodus 21:24; Leviticus 24:19–20; Deuteronomy 19:21; see also Matthew 5:38). The use of the word “double” suggests that in this instance the Lord is prescribing a punishment considerably beyond what he stipulated in the Pentateuch. Researchers, however, have concluded that the term translated as “double” does not in fact mean “twice as much,” but means instead “produce a duplicate” and so a “matching equivalent,” an understanding that works well in passages as Isaiah 40:2 and Jeremiah 16:18 and does justice to the Lord’s reputation as being righteous in his punishments. This understanding also lines this text up with the earlier part of the verse: “Pay her back as she…” as well as the next verse: “Give her a like measure of torment.” Furthermore, as her cup was already full (Revelation 17:4), mixing a double portion for her cup is problematic. So we conclude that we ought to translate the line as “repay her in matching equivalent for her deeds.”
6 Pay her back as she herself has paid back others, and repay her double for her deeds; mix a double portion for her in the cup she mixed.