isaiah 66:7 Before she travailed, she brought forth; before her pain came, she was delivered of a man child. - Free Bible Online

      7. she--Zion.
      Before . . . travailed . . . brought forth--The accession of numbers, and of prosperity to her, shall be sudden beyond all expectation and unattended with painful effort (Isa 54:1, 4, 5). Contrast with this case of the future Jewish Church the travail-pains of the Christian Church in bringing forth "a man child" (Re 12:2, 5). A man child's birth is in the East a matter of special joy, while that of a female is not so; therefore, it here means the manly sons of the restored Jewish Church, the singular being used collectively for the plural: or the many sons being regarded as one under Messiah, who shall then be manifested as their one representative Head.

JFB.