St. Justin
(100 - 165)
Dialogia contra Trypho, Chapter 84
"Moreover, the prophecy, 'Behold, the virgin shall
conceive, and bear a
son,' was uttered respecting Him. For if He to whom
Isaiah referred was
not to be begotten of a virgin, of whom did the Holy
Spirit declare,
'Behold, the Lord Himself shall give us a sign: behold,
the
virgin shall
conceive, and bear a
son?' For if He also were to be
begotten of sexual
intercourse, like all other first-born sons, why did
God say that He would
give a sign which is not common to all the first-born
sons?