These chapters set in the eighth century deal have the context of the rising Assyrian threat — and the fears and anxiety of the the people of God in their day just as we are. The prophet’s words from God especially address personal questions of security and certainty and the central role of faith. Faith in God dominates this section of the book and challenge us how to think about faith in God, the reasons for it, and what faith in God looks like practically.
Whereas earlier in Isaiah we saw themes of repentance, judgment and future grace painted vividly (Isaiah 1-12) and heard oracles of God to particular nations (Isaiah 13-24), God now address the world in general, and His covenant people's place in that world. His call to them is faith in Him when nothing is reliable or trustworthy.
If you find yourself vacillating with weak faith mixed in worldliness, or fearful amid a day where nothing seems constant or as it should be, Isaiah invites us to trust in God and discover what that looks like. If your attention is scattered and your heart is weak, or you remember loving the Lord much more in your youth than you did in the present day, Isaiah invites you to build and enrich your faith in God.
In a sense, Isaiah 14-35 are well-described by this quote from C.S. Lewis on what God is doing by faith:
“Imagine yourself as a living house. God comes in to rebuild that house. At first, perhaps, you can understand what He is doing. He is getting the drains right and stopping the leaks in the roof and so on; you knew that those jobs needed doing and so you are not surprised. But presently He starts knocking the house about in a way that hurts abominably and does not seem to make any sense. What on earth is He up to? The explanation is that He is building quite a different house from the one you thought of - throwing out a new wing here, putting on an extra floor there, running up towers, making courtyards. You thought you were being made into a decent little cottage: but He is building a palace. He intends to come and live in it Himself.”