Mary said to the angel, "How can this be, seeing I am a virgin?"
      (3.) The child she shall conceive is a holy thing, and therefore must not be conceived by ordinary generation, because he must not share in the common corruption and pollution of the human nature. He is spoken of emphatically, That Holy Thing, such as never was; and he shall be called the Son of God, as the Son of the Father by eternal generation, as an indication of which he shall now be formed by the Holy Ghost in the present conception. His human nature must be so produced, as it was fit that should be which was to be taken into union with the divine nature.