21 We ask further, of whom comes He and how? And this Esaias tells us: Behold! The virgin shall conceive in her womb, and shall bring forth a Son, and they shall call His name Emmanuel. This the Jews contradict, for of old it is their wont wickedly to oppose the truth: and they say that it is not written “the virgin,” but “the damsel.” But though I assent to what they say, even so I find the truth. For we must ask them, If a virgin be forced, when does she cry out and call for helpers, after or before the outrage? If, therefore, the Scripture elsewhere says, The betrothed damsel cried, and there was none to save her, does it not speak of a virgin?
But that you may learn more plainly that even a virgin is called in Holy Scripture a “damsel,” hear the Book of the Kings, speaking of Abishag the Shunamite, And the damsel was very fair: for that as a virgin she was chosen and brought to David is admitted.
Source: Catechetical Lectures (New Advent)