“Go now!
Write it before them on a tablet!
Inscribe it in a book!
Thus it may be for the time to come.
Let this be a witness forever!”
Isaiah wanted them to preserve his oracles. He wanted them to write these oracles on a tablet. Then they were to keep them on a scroll in some kind of book. Thus they would become a lasting witness about things to come in the future. Apparently, this was done.