Now, what is especially noticeable in these three [St Irenaeus, Tertullian and St Jerome] writers, is, that they do not speak of the Blessed Virgin merely as the physical instrument of our Lord's taking flesh, but as an intelligent, responsible cause of it; her faith and obedience being accessories to the Incarnation, and gaining it as her reward. As Eve failed in these virtues, and thereby brought on the fall of the race in Adam, so Mary by means of the same had a part in its  restoration. You [Pusey] surely imply, pp. 151-156, that the Blessed Virgin was only a physical instrument of our redemption; "what has been said of her by the Fathers as the chosen vessel of the Incarnation, was applied personally to her," (that is, by Catholics,) p. 151, and again "the Fathers speak of the Blessed Virgin as the instrument of our salvation, in that she gave birth to the Redeemer," pp. 155, 156; whereas St. Augustine, in well-known passages, speaks of her as more exalted by her sanctity than by her relationship to our Lord. However, not to go beyond the doctrine of the Three Fathers, they unanimously declare that she was not a mere instrument in the Incarnation, such as David, or Judah, may be considered; they declare she co-operated in our salvation not merely by the descent of the Holy Ghost upon her body, but by specific holy acts, the effect of the Holy Ghost within her soul; that, as Eve forfeited privileges by sin, so Mary earned privileges by the fruits of grace; that, as Eve was disobedient and unbelieving, so Mary was obedient and believing; that, as Eve was a cause of ruin to all, Mary was a cause of salvation to all; that as Eve made room for Adam's fall, so Mary made room for our Lord's reparation of it; and thus, whereas the free gift was not as the offence, but much greater, it follows that, as Eve co-operated in effecting a great evil, Mary co-operated in effecting a much greater good.

Newman's reply to Pusey's Eirenicon