en_tn_condensed/isa/45/21.md

Yahweh continues speaking to the refugees. (See: Isaiah 45:20)

Let them counsel together

"them" are the people who might challenge Yahweh's power to foretell the events.

Who has shown this from long ago? Who announced it? Was it not I, Yahweh?

Yahweh uses questions to emphasize that he was the one who told them these things would happen. AT: "It was I, Yahweh, who told you these things long ago" (See: rc://en/ta/man/translate/figs-rquestion)