As a Lutheran pastor I was trained to be a dogmatician. Theology was doctrine, and doctrine was the sum and substance of the Christian faith. Dogmatic theology (which is good and necessary) is still the only lens through which most Lutherans read Scripture.

Viewed through such a lens next Sunday's Old Testament lesson becomes a statement about the Bible and its inerrancy, not about the Incarnate Word, the Eternal Son, who is the Truth. My translation is as follows:

For as the rain and snow fall from the heavens, and do not return there; 
     but water the earth causing it to bring forth and sprout; giving seed to the sower         and bread to the eater ... 
so shall my Word (Christ) be! which goes out from my mouth - 
     it (He) shall not return to me fruitless, but shall accomplish that which I delight in         and shall achieve the thing for which I send it (Him).

For you shall go out brimming with joy, and be led out in peace [like a bride]. 
     The mountains and hills shall break forth into singing before you, 
          and all the trees of the fields shall clap their hands.

instead of the thorn, 
     the cypress will grow
instead of the brier, 
     the myrtle will spring up.
And it (my Incarnate Word) shall make a name for the LORD;
     an everlasting sign that shall not be cut off.

We do well, first of all, not to think of this segment of Isaiah (or indeed any of the prophets) as simple narrative, reportage or religious information; and certainly not as poetry: but as liturgy! As words given to the prophet, by the Spirit, in the form of ready-to-pray liturgy concerning the promise of the Incarnate Word of God.

Does Isaiah also have Scripture in mind when he pens this liturgy? Without doubt because the written Word and the Incarnate Word can never be separated. But still we must distinguish

Jesus is the rain of heaven who waters the earth with the life giving waters of baptism. He is the snow whose blood covers the scarlet of our sins (Is. 1:18). He is the one who gives us the blessed bread of his flesh to eat in Eucharist, and he does not return to the Father fruitless, but with his baptismally-cleansed and spotless Bride the Church at his side.

He is the name of the Lord; and the everlasting Sign of salvation for all sinners that will never be cut off. He will endure unto the ages of ages, to nourish and cherish his Bride  so that she/we will never want again.

But speaking of Scripture much the same can be said. As often as God's revealed Word is given voice in the church, its utterance like radio waves penetrates the church walls; it scatters faster than the speed of light; and is heard by and sanctifies all things visible and invisible.

The church in heaven rejoices with the voice of many waters when the church on earth utters this Living Word. The church on earth is refreshed and renewed in righteousness and holiness. (Eph. 4:24) But the devils tremble as another installment of their judgement locks into place.

The very bricks of the church are blessed. They retain the aroma of the gospel of Christ as often as God speaks in Sacred Scripture by the mouths of his children. The sick are made healthy; the disconsolate are given new hope; the babies in the womb leap for joy over their true Ancestor, Christ.

That is the right way to think about this verse, but there is also a wrong way that we should avoid, immortalized by the slogan "Sola Scriptura" (Scripture Alone). This phrase begs the question and means nothing as it stands; but demands an explanation instead. But once explanation commences Scripture is no longer "alone" but now there the church's inspired interpretation taking place. And so in this way "Sola Scriptura" is a logical fallacy, and fallacies have no place among God's people.

Scripture is the voice of God, and whenever God opens his mouth, he speaks Jesus. He speaks the incarnation of the eternal Word who is in him from before the foundation of the world. But who, now for love's sake, proceeds into the world "for us men and for our salvation."

Scripture is unique. Whereas all other scribblings ever scribbled (however doggerel-ish or profound) proceed from the mind of man. Scripture is that unique body of writing that proceeds from the mind of God. That is what makes Scripture unique and gives it all its other qualities by which man is uberly-blessed. It is God's utterance that comes down from heaven like the rain and the snow, renews the face of the earth, and does not return except bringing with it a harvest for God in Christ.

You are that harvest! And so rejoice in this Divine Word spoken by the lips of Isaiah his prophet.