I answer that, on this point there are various opinions. For some have held that the fomes was entirely taken away in that sanctification whereby the Blessed Virgin was sanctified in the womb. Others say that it remained as far as it causes a difficulty in doing good, but was taken away as far as it causes a proneness to evil. Others again, that it was taken away as to the personal corruption, by which it makes us quick to do evil and slow to do good: but that it remained as to the corruption of nature, inasmuch as it is the cause of transmitting original sin to the offspring. Lastly, others say that, in her first sanctification, the fomes remained essentially, but was fettered; and that, when she conceived the Son of God, it was entirely taken away. In order to understand the question at issue, it must be observed that the fomes is nothing but a certain inordinate, but habitual, concupiscence of the sensitive appetite. for actual concupiscence is a sinful motion. Now sensual concupiscence is said to be inordinate, in so far as it rebels against reason; and this it does by inclining to evil, or hindering from good. Consequently it is essential to the fomes to incline to evil, or hinder from good. Wherefore to say that the fomes was in the Blessed Virgin without an inclination to evil, is to combine two contradictory statements.
In like manner it seems to imply a contradiction to say that the fomes remained as to the corruption of nature, but not as to the personal corruption. For, according to Augustine (De Nup. et Concup. i.), it is lust that transmits original sin to the offspring. Now lust implies inordinate concupiscence, not entirely subject to reason: and therefore, if the fomes were entirely taken away as to personal corruption, it could not remain as to the corruption of nature.
It remains, therefore, for us to say, either that the fomes was entirely taken away from her by her first sanctification or that it was fettered. Now that the fomes was entirely taken away, might be understood in this way, that, by the abundance of grace bestowed on the Blessed Virgin, such a disposition of the soul's powers was granted to her, that the lower powers were never moved without the command of her reason: just as we have stated to have been the case with Christ (Question [15], Article [2]), who certainly did not have the fomes of sin; as also was the case with Adam, before he sinned, by reason of original justice: so that, in this respect, the grace of sanctification in the Virgin had the force of original justice. And although this appears to be part of the dignity of the Virgin Mother, yet it is somewhat derogatory to the dignity of Christ, without whose power no one had been freed from the first sentence of condemnation. And though, through faith in Christ, some were freed from that condemnation, according to the spirit, before Christ's Incarnation, yet it does not seem fitting that any one should be freed from that condemnation, according to the flesh, except after His Incarnation, for it was then that immunity from condemnation was first to appear. Consequently, just as before the immortality of the flesh of Christ rising again, none obtained immortality of the flesh, so it seems unfitting to say that before Christ appeared in sinless flesh, His Virgin Mother's or anyone else's flesh should be without the fomes, which is called "the law of the flesh" or "of the members" (Rm. 7:23,25).
Therefore it seems better to say that by the sanctification in the womb, the Virgin was not freed from the fomes in its essence, but that it remained fettered: not indeed by an act of her reason, as in holy men, since she had not the use of reason from the very first moment of her existence in her mother's womb, for this was the singular privilege of Christ: but by reason of the abundant grace bestowed on her in her sanctification, and still more perfectly by Divine Providence preserving her sensitive soul, in a singular manner, from any inordinate movement. Afterwards, however, at the conception of Christ's flesh, in which for the first time immunity from sin was to be conspicuous, it is to be believed that entire freedom from the fomes redounded from the Child to the Mother. This indeed is signified (Ezech. 43:2): "Behold the glory of the God of Israel came in by the way of the east," i.e. by the Blessed Virgin, "and the earth," i.e. her flesh, "shone with His," i.e. Christ's, "majesty."
