What does Isaiah 66:8 mean?

Who has ever heard of such a thing? Has anyone seen anything like this? Can a country be born in a single day? Can a nation come to life all at once? But as soon as Zion goes into labor, her children are born. Isaiah 66:8 - Modern Text Bible

(God is describing a sudden, miraculous restoration of his people—something unheard of, but possible with him.)