The grass withers, the flower fades repeats the first line of the previous verse for emphasis (see the comments there). Good News Translation adds the word “Yes” to draw attention to the repetition.

But the word of our God will stand for ever: This contrasting clause is the climax of the subsection. It contrasts God’s eternal word with the fragility of humans (especially the Babylonians). His word will always remain true. This theme is important in the latter half of this book (see, for example, 55.10-11). The word of our God refers specifically to the promises in verses 2 and 5. It does not point to the whole Bible here. Will stand is literally “will arise” or “will stand up,” meaning “will endure and be true.” As noted before, the Hebrew word rendered for ever generally means “for a very long time,” rather than “for eternity.” Contemporary English Version provides a helpful model for this line: “but what our God has said will never change.”

Translation examples for this verse are:

• Grass withers, flowers fade,
but our God’s promises [or, word] will always remain true.”

• Grass withers and flowers fade,
but what our God promises will endure forever.”

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 .