Isaiah speaking to Israel is in the midst of many prophecies, some more immediate and not good. God tended to, even in the midst of pronouncing judgement, also provide hope for His people. I interpret these verses to speak of the same thousand years as mentioned in Revelation, the Millennium.
On this mountain the LORD of hosts will make for all peoples a feast of rich food, a feast of well-aged wine, of rich food full of marrow, of aged wine well refined. 7
And he will swallow up on this mountain the covering
that is cast over all peoples, the veil that is spread over all nations. 8
He will swallow up death forever; and the Lord GOD will wipe away tears from all faces, and the reproach of his people he will take away from all the earth,
for the LORD has spoken. 9
It will be said on that day
, "Behold, this is our God; we have waited for him, that he might save us. This is the LORD; we have waited for him; let us be glad and rejoice in his salvation."