Does one give birth before the contractions!
Rashi: Tziyon, who give birth, gave birth to her children. I.e. her children will gather into her. She was desolate and bereft of them; it is as if she gave birth to them now, without contractions, for the Nochrim will bring them to her.
Radak: The salvation will come suddenly to Yisrael. Yerushalayim is compared to a mother, and Yisrael to children.
Malbim: A long time before the redeemer, a small number of Bnei Galus will fix their residence in Yerushalayim. After dwelling there many years, Chevlei Yoledes will come - the war of Gog and Magog, and then will come the general gathering. Yerushalayim already had a small birth before the contractions.
Why does it say "b'Terem Tachil" and "b'Terem Yavo Chavel"?
Malbim: Not only was birth before the contractions - it was even before the time for contractions, years before the Ge'ulah!
What is the meaning of "v'Himlitah"?
Rashi: Emergence of anything enveloped is called Hamlatah.
Radak: It is birth - "Shamah Kinenah Kipoz va'Timalet" (34:15).
Why does it specify "Zachar"?
Radak: A male is better and stronger than a female. His parents rejoice over him more than over a female. So will be the generation of the salvation.
Malbim: It did not yet give birth to a great nation, only a small number, therefore it says "Zachar" (singular).
