Let us open with an invocation and Luther's Morning Prayer:

I thank you my heavenly Father through Jesus Christ my Lord, that you have kept me this night from all harm and danger; and I pray that you would keep me this day from sin and every evil, that all my doings may please you.  For into your hands I commend myself, my body and soul and all things.  Let Your holy angel be with me that the evil foe have no power over me.  Amen.
 

And I heard the voice...
Not everybody hears the voice.  The effect of the vision is to both receive some of the Jews and to harden the rest of the Jews.  The Word of God does not always have humble hearers. The majority are proud, whose reason is not mortified/brought low and whose faith is in their carnal/sinful flesh.

Whom shall I send?
Not all prophets received the teaching office the first time it was offered.  For example, Moses and Jonah both refused.

What about us today?  Who would speak publicly against this nation or who would speak publicly against their own church body?

Isaiah accepts the call after being risen from the curse of death to life, has been strengthened by the burning coal, and has been made a different man.  He is ready to face the great difficulty with faith in Christ.

And He said, "Go, and say to this people...
The emphasis is on the word "this" rather than "My" as in this cursed or rejected people.  God is angry that people live to please themselves, will not learn from Him how to view themselves, and will not deny themselves.  The pastors and people are in this together.

Make the heart of this people dull...so that they do not return and be healed.
The point of this passage is to show God's attitude to those who are hardened in heart, who reject the faith, who reject the Gospel.  He forsakes them.

Then I asked, How long?  And He said, "Until...
As if to say, 'You will not be reformed until death has snatched you away.' Meaning, you will never be reformed.  Don't read this as if it pertained only to that present generation of Israel. There is no promise here for the children.

The Lord  has removed men far away.
That is, He will scatter them among the nations.

And the forsaken places are many...
Another way to read this is, "What will have been forsaken?"

And this is the meaning: God does not snatch away after the manner of Satan, who rages in such a way that he tries to uproot everything altogether, but the Lord always preserves a remnant after the evil have been destroyed.
 

And yet a tenth will remain...
Like a little branch from a forest.  This could be read as a curse, as in 90% will be destroyed.  Or, this could be read as a blessing, as in 10% will be saved.

A holy seed is its stump.  Or...this is the stump of Jesse.  Or...this is the Christ.
So, this is not concerning the Babylonian Captivity in which the corrupt people were enslaved and then corrupt people returned.  This is concerning the Roman Captivity in which Jesus served His ministry.  The holy seed is Christ who is the Seed of the church, the body of Christ, the temple of the Holy Spirit, in which there is no ungodly person but all are righteous in Christ.
 

Let us close with the Lord's Prayer.