Isaiah 46 & 47 contain two warnings to two different audiences, both which strongly affirm the majesty and Sovereignty of the Holy One of Israel, but which also serve as comforts for God’s faithful people.
The first in chapter 46, we’ll see that God carries His people, and it is unconscionable that His people then persist in carrying idols! There is herein a “warning of comfort”.
The second message is clearly to Babylon - and comes due to their treatment of His people as well as their pride and security in themselves. But the real audience here is the people of God, and the “warning of comfort” is in the fact that God does see, and that He will make all things right—that His justice and salvation are imminent.
In these chapters there is great comfort for us in abiding trust in Him as the one true God, casting aside our idols, and trusting Him to bring justice when we are wronged— He is in control!