One of the texts in which S. Thomas brings up the concept of “bonum prolis” discussed in my last post is in an article of the Commentary on the Sentences [lib. 4, d. 30, q. 2], in which he shows that the marriage between Our Lady and S. Joseph was a perfect marriage. Matthias Joseph Scheeben quotes this passage as part of his proof that not only is the Our Lady’s marriage to S. Joseph a valid marriage, but it is the most perfect marriage, lacking none of the essential goods of marriage, though of course its virginal nature meant that these goods were possessed in a unique way. Here is a rough translation of the key part of Scheeben’s proof:
It is clear […] that this marriage exceeds all other marriages not only in sanctity and dignity, but in its very perfection as marriage, namely in regard to the two principle goods of marriage, the bonum prolis and the bonum sacramenti.
With regard to the bonum prolis: like all marriages this one was ordered by God, and therefore from within and essentially, to bringing about the possibility of a susceptio prolis. So this marriage was more excellent than every other virgin marriage, since it shared with the matrimonium consummatum the blessing of fruitfulness, since in this marriage the spouses were really to be given and entrusted with a fruit. And though this fruit was not generated by the spouses through carnal use of marriage, nevertheless, through the intention of the divine begetter and on account of the spiritual union of the spouses, the fruit belonged to both of them no less than in a natural marriage. Moreover, this marriage is also more excellent than any non-virginal marriage since its fruit is essentially and absolutely holy, and at the same time the two spouses through their common virginal consecration to God cooperate in bringing about this fruit much more than others cooperate through fleshly union in the generation of natural offspring.
The bonum sacramenti is the marriage bond by which a union more lofty and intimate than other human unions is established, in that, through the will of God, one person is so joined to another […] that they form an inseparable whole, and in and through the whole thus formed God takes them into possession as His own organ for the fulfillment of a certain service. Thus the perfection of the bond is by so much higher as the service for which one person is joined to another is holier, and as the belonging-to God (Angehörigkeit an Gott) through which and for which one person takes the other to himself is greater. Now, the bond between Joseph and Mary is in both respects beyond comparison more excellent not only than any natural (pre- or non- Christian) marriages, but also than all Christian marriages. For, the conception and rearing of Christ is an infinitely more excellent purpose than the generation and rearing of mere men, who are to be members of Christ, and Mary is far more an organ of God and a member of Christ than all who are consecrated organs of God and members of Christ through baptism. (Handbuch der katholischen Dogmatik, Volume V, Freiburg 1882, §1579-1580)