This passage closes what has traditionally been called Second Isaiah. One indicator of the validity of that designation is the way this text parallels Isaiah 40:1-11 (the opening of Second Isaiah). The two promises surround this section of the book, serving as an inclusio or "bookends," both texts centering on God's enduring word as the certain basis for all the good things God announces in the intervening chapters.
The Isaiah 40 passage opens in the imperative voice, found in many oracles of Second Isaiah: "Comfort my people….Get you to a high mountain….Do not fear….Sing….Listen….Remember….Rouse yourself…." The imperatives abound in this material, not as difficult commands to be fulfilled, but as wonderful invitations to be accepted. This closing passage should be heard in the same way--not, "Seek the LORD," you must; but "Seek the LORD," you can! God has come and made the divine self available to human seeking. Such a wonder is what makes God's thoughts higher than human thoughts--an approachable God is a great surprise.
The text has a clear rhetorical structure in making its case: "Seek…forsake…return…for…for...for…for…for." The several "fors" explain why the people should seek. Seek God, because…because God pardons abundantly; because God's ways are not your ways; because God's ways are higher than the earth; because God's word will not fail; because God means to lead you out of exile with rejoicing. The promise overwhelms the imperative and provides the basis for Israel's positive response to God's invitation.
Isaiah uses the example of the rain and snow to illustrate the power of God's word. Rain and snow come from God and cannot be coerced. Once fallen, they cannot be called back, but do what they came to do: provide water to nourish the earth and give life to the crops. God's word is the same, says the prophet: it too comes from above and does what God intends--nourishing and feeding. Elsewhere in Second Isaiah we learn more about the "purpose" that God means to accomplish through the word of promise: Cyrus will carry out God's "purpose" (same Hebrew word), which is to rebuild Jerusalem (44:28). And God's word will accomplish even more than that: it will not return even when Jerusalem is restored, but will call the ends of the earth to be saved: "To me every knee shall bow, every tongue shall swear" (45:22-23). The point is not to force worship by divine power but to invite Israel and the nations to turn away from "praying to a god that cannot save" (45:20) and turn to a God who can (46:1-4).
Again in this text, God's renewal is not only for people but for the entire creation. When God acts, everything is transformed and restored: mountains, hills, and trees of the field will have occasion to praise their Creator because their "enemies" (thorns and briers), too, will be removed. The text is poetry, of course, not deep ecology. The point is not that thorns and briers are beyond God's concern (just as human "enemies" are not), but that finally God removes pain and death from creation.
6 Seek the Lord while he may be found,
call upon him while he is near;
7 let the wicked forsake their way,
and the unrighteous their thoughts;
let them return to the Lord, that he may have mercy on them,
and to our God, for he will abundantly pardon.
8 For my thoughts are not your thoughts,
nor are your ways my ways, says the Lord.
9 For as the heavens are higher than the earth,
so are my ways higher than your ways
and my thoughts than your thoughts.
10 For as the rain and the snow come down from heaven,
and do not return there until they have watered the earth,
making it bring forth and sprout,
giving seed to the sower and bread to the eater,
11 so shall my word be that goes out from my mouth;
it shall not return to me empty,
but it shall accomplish that which I purpose,
and succeed in the thing for which I sent it.
12 For you shall go out in joy,
and be led back in peace;
the mountains and the hills before you
shall burst into song,
and all the trees of the field shall clap their hands.
13 Instead of the thorn shall come up the cypress;
instead of the brier shall come up the myrtle;
and it shall be to the Lord for a memorial,
for an everlasting sign that shall not be cut off.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org