20 Assemble yourselves and come; draw near together, ye that are escaped of the nations: they have no knowledge that set up the wood of their graven image, and pray unto a god that cannot save.
21 Tell ye, and bring them near; yea, let them take counsel together: who hath declared this from ancient time? who hath told it from that time? have not I the Lord? and there is no God else beside Me; a just God and a Saviour; there is none beside Me.
22 Look unto Me, and be ye saved, all the ends of the earth: for I am God, and there is none else.
God is speaking to the nations now, not just to Israel. Salvation is for all mankind, not just the Jews. He call the nations to assemble together, and it would seem that the time here is after the Tribulation judgments. He is speaking to those who have escaped, and He warns them that those who make idols of wood and pray to graven images are praying to gods who cannot save anyone from anything.
God, speaking to Isaiah, tells him to summon the nations and let them present their arguments for the worship of gods they have made with their own hands, lifeless gods who can do nothing.
Once again, He declares that He alone is God, and there is no other. He alone can save us.