But why is He conceived not of a Virgin merely, but of a Virgin espoused? First, that by the descent of Joseph, Mary’s family might be made known; secondly, that she might not be stoned by the Jews as an adulteress; thirdly, that in her flight into Egypt she might have the comfort of a husband.
The Martyr Ignatius [margin note: vid. Ign. ad Eph. 19] adds yet a fourth reason, namely, that His birth might be hid from the Devil, looking for Him to be born of a wife and not of a virgin.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).