J.M.J. "Christ chose to be born of a Virgin . . . (so) that the devil should not be aware that salvation had been born for the human race, and through the obscurity of that spiritual conception, when he saw Him no different than others, should believe Him born in no different way than others. For when he observed that His nature was like that of all others, he thought that He had the same origin as all (others) had. And he dd not understand that He was free from the bonds of transgression, because he did not find Him a stranger to the weakness of morality."
--Pope Saint Leo the Great (440-461), Sermon 22, II (in PL54, 193B-199A), as quoted by the Reverend Luca M. Genovese, "The Significance of the Virgin Birth in Saint Leo the Great" in Missio Immaculatae International (September/October 2015), 5.