The key to this section of Isaiah is the repetition of the concept of the Lord being the only God and, therefore, the only Savior of the world.  Notice the repetition and restatement of this idea in Isaiah 45:14, 18, 21 (twice), 22.  What’s important to remember is that God makes these exclusive, narrow claims for His people.  Isaiah is not written for the agnostics or atheists, but for the Church.  All along our study Isaiah has pleaded with us to part company with society and its idolatry.  So, here we’re shown one God (Isaiah 45:14, 18-21), two destinies (Isaiah 45:15-17), and one way (Isaiah 45:22-25).  The last section contains an invitation/application.  Isaiah 45:24 is an excellent way to move from Isaiah’s Gospel to the Gospel of Jesus Christ, the One through whom righteousness is received.  Help God’s people see their idolatry and urge them to “turn to” the Lord and “be saved…”  An interesting hermeneutical issue is the way in which Paul picks up on Isaiah 45:23 in Philippians 2:10-11.

In Isaiah 43:22-28 God provides a description of a major sin His people were committing against Him.  Something had gone wrong with their sacrificing (Isaiah 43:23-24).  We know from Isaiah 1:11-14 that there was all kinds of religious activity going on, but no worship.  The fatal combination of going to worship and sinning was nauseating God (cf. Isaiah 1:13).  It’s pretty easy to make a connection with our current situation where the Church is looking more and more like society and less and less like the Savior.  We have more ministries operating than ever before, but we share the same morality as the world.  Thankfully, tucked in the middle of the negative assessment of our worship experiences is the Gospel of Isaiah 43:25.  In Christ, those who have their sins forgiven also have the desire and capacity to worship God in a way that satisfies Him.

Isaiah 43:10-19 is controlled by the opening declaration of God: “You are my witnesses…”  The sermon is controlled by the reason for our status as witnesses/servants: “…that you may know and believe me and understand that I am he” (cf. Isaiah 43:10).  This logic should catch us all off guard for a moment.  We don’t expect this reason for being witnesses.  We expect to be witnesses for God so that others might know Him.  Instead, we learn that God has allowed us to experience His transforming power so that we might know Him.  It’s not, then, about productivity, but about intimacy.  The rest of the section highlights the unique status God has among the gods.  We Christians are the ones who say to the world, “God is who He says He is and can do for you what He’s done for me–save.”  That implies, of course, that we are experiencing His transforming power.  Notice the question in Isaiah 43:19.  Surely, we are a people who perceive the “new thing” God is doing.

Mixed in with comforting Scripture in Isaiah 40-66 are comforting commands such as Isaiah 43:1, 5.  Sermons in this section should include some analysis of God’s self-description.  Notice all the titles for God that are stated and restated.  Allow the structure of the section to drive the sermon.  In this case, God provides several reasons why His people should not be afraid.  It’s always a timely message in a scary world.  If you’re looking to allow the Gospel to give the definitive reason why we need not fear, it might be found in Isaiah 43:3-4.  Ultimately, God did not ransom us by giving us Egypt or Cush or Seba.  Instead, we were ransomed when God gave His Son “in exchange” for our lives (cf. Isaiah 43:3-4).  So, fearless Christians are those who believe Isaiah’s Gospel.

Isaiah 42:18-25 is a terrible picture of the collective condition of God’s people.  Theology is conveyed through a description of spiritual disabilities (unable to hear and see God’s laws), the terrible response of God’s punishment, and a question (cf. Isaiah 42:23).  Every Sunday is an opportunity for us to test our listening abilities.  True believers have ears that can hear.  The reason: later in Isaiah 50:5 we learn of God’s Servant who has perfect spiritual hearing.  Faith-family members respond to the question in Isaiah 42:23: “We will give ear to this. We will attend and listen…”  Those who are in Christ have inherited His supernatural hearing.  Out of the collective condition of God’s people–spiritual deafness–comes a remnant of people who do hear Isaiah’s prophecy and “take it to heart” (cf. Isaiah 42:25).

Isaiah 42:5-9 declares three things that “the Lord” will do to His people: “I have called you…I will take you…I will give you…”  This is a guarantee that His people will serve Him and carry out His purpose in the world.  Cf. Isaiah 42:6-7, especially the goal of being “a light for the nations…”  The theology for the Church is being conveyed through this description of God’s initiative, followed by the purpose or goal God has in mind.  If Isaiah 42 is relevant at all it’s because of a sequence like this: God’s people fail to function as His servants, God’s Servant succeeds (through His perfect life, substitutionary death for sin/sinners, resurrection, ascension, dispatching His Spirit), and all who trust Him begin to fulfill Isaiah’s prophecy by making disciples all over the globe.

One key to understanding the theology of Isaiah 42:1-4 is to highlight the contrast between God’s Servant (Isaiah 42:1) and the idols of the previous chapter.  Unlike the idols, God’s Servant will actually deliver.  That is because He is Spirit-driven or Spirit empowered (“I have put my Spirit upon him”).  Then the rest of verse 1 through verse 4 describe what He will do and how He will do it.  The structure is very simple.  The theology is conveyed through the description and is designed to bolster our faith in God alone, rather than choosing to worship all our American idols.  Isaiah 42:3 describes how our Savior deals with us in our weakness.  On the cross Jesus experienced total weakness-to-the-point-of-death so that He could share God’s strength with us.  Philippians 2:7-8 describe Jesus like Isaiah did (“servant”).  Our Savior will bring justice only because He suffered the wrath of God for our sins.  Because He did that for us, instead of justice, we received mercy so we can now administer justice and mercy to those in need.

Isaiah 41:1-14 teaches through a contrast between the coastlands and God’s servant, Israel (cf. Isaiah 41:1, 8).  The coastlands are afraid (Isaiah 41:5).  God’s people trust that He has not cast them off, despite their rebellion.  Despite living in a scary world where the godless are in power, God commands them, “fear not.”  It’s an extremely difficult command to obey in life-threatening circumstances.  We’re afraid in times when our weakness is exposed.  Isaiah 41:14 reminds us how weak we are!  It takes faith for God’s people to be brave. It takes faith to receive God’s shared strength.  Our faith is bolstered when we read of our Savior in Psalm 22:6.  In utmost weakness, Christ dies to give us an opportunity to share God’s strength.  We’re not afraid from a position of strength.  In light of the promise, then, in Isaiah 41:10, true or false: “I can’t take it any more!”?

In Oswalt’s commentary on Isaiah 41 he writes: “This argument will be repeated and intensified several times in the next few chapters as this court case continues” (p. 459).  You have at least two options: (1) preach the repeated themes as you encounter them along the way or (2) preach the theme in one location, adding any material from the “intensified” places.  I choose the latter option as a way of keeping a series moving along in a long book such as Isaiah.  I’ve found it helpful to read through the section and look for the repetition/restatement.  That allows you to scan for material you want to bring into the one sermon on the presented theme.  More than likely, the same theological message (how the section functions for the church) will be presented throughout the repetition.

The bulk of Isaiah 40 is devoted to showing our incomparable God (Isaiah 40:12-26).  The description of our God makes our question in Isaiah 40:27 inconceivable.  Of course God knows how difficult our way is in a world where the godless are in power!  Then, after restating God’s resources of strength and knowledge (Isaiah 40:28), we learn that all His power is transferable to those who “wait” for Him (cf. Isaiah 40:29-31).  Our Lord continues to save His people because His strength is added to our weakness so we keep putting on fresh strength each day.  Instead of being overcome with circumstances, God stabilizes our emotions and spirits.  So, is it true or false when a Christian says in frustration: “I can’t take it anymore!”?  And, of course, we know that all this available strength came as a result of Jesus’ experience of weakness on the cross.  He experienced ultimate weakness so we could experience ultimate strength as we trust Him.