The tone of Isaiah shifts in chapter 40, and the focus narrows as extended words of judgement give way to descriptions of what the Lord is about to do. There is still a pointed interest in sin, and idolatry receives particular attention, but much more of the narrative now focuses on the Servant who is coming, and the salvation God intends to accomplish.
This emphasis on the future catches my eye; I notice how often in this section of the book the Lord speaks of His ability to tell it. For example (to choose one among many): “I make known the end from the beginning,” God says, “from ancient times, what is still to come” (Isa 46:10).
A couple things flow from this, like how this sort of declaration puts God in sharp contrast with idols, for whom the future is dark. And when I think about idols not as ancient stone or metal objects pre-literate societies revered because they didn’t have science, but rather as anything that competes for the energy and affections due God (as discussed in recent books like Tim Keller’s Counterfeit Gods, or Alan & Debra Hirsch’s Untamed), God’s potent words become stunningly relevant.
Another implication: knowing that He has a plan that means blessing for many instills hope. And a third: fulfillment of previous promises engenders faith for the days ahead. Both of these encourage me, and nurture the faith and hope I want to be steady and strong in my life.
One more thing I see here is how little Isaiah comments on what is being said. The prophet records the words of the Lord, and puts readers in His very midst. They hear how God wants to be known for the ability to see the future clearly and to talk about it with a level of confidence far beyond any other–and then it’s up to them to draw their own conclusions.