Intimacy in our union with Christ
As God's loving-kindness is ineffable and His love for our race surpasses human speech and reason, so too it belongs to the divine goodness alone, for this is "the peace of God which passes all understanding" (Phil. 4:7). Likewise it follows that His union with those whom He loves surpasses every union of which one might conceive, and cannot be compared with any model.
Therefore even Scripture needed many illustrations to be able to express that connection, since one would not suffice. In one place it employs the figures of an inhabitant and a dwelling, in another those of a vine and a branch, here that of a marriage, there that of members and a head. None of those figures is adequate for that union, for it is impossible from these to attain to the exact truth. Above all it is necessary that the union should conform to friendship-yet what could be adequate for divine love?
It would appear that marriage and the concord between head and members especially indicate connection and unity, yet they fall far short of it and are far from manifesting the reality. Marriage does not so join together that those who are united exist and live in each other, as is the case with Christ and the Church. So the divine apostle, speaking of marriage, says, "this is a great mystery," and adds, "I speak of Christ and the Church" (Eph. 5:32), showing that it is not marriage but union with Christ which he sets up for admiration. The members are joined to the head; they are alive because they are joined and die if they are separated. But it appears that the members of Christ are more closely joined to Him than to their own head, and that it is even more by Him that they live than by their concord with it. This is plain from the blessed martyrs, who gladly suffered the one (ie. dismemberment of their bodies) but would not even hear of the other, for they gave up their heads and limbs with pleasure, but could not even by word revolt from Christ.
So I come to that which is strangest. To whom else could one be more closely united than to oneself? Yet this very unity is inferior to that union. For each of the spirits of the blessed ones is identical with himself, yet it is united to the Saviour more than to him. It loves the Saviour more than itself, and of this Paul will bear witness by the saying in which he wishes that he were "anathema from Christ for the sake of the salvation of the Jews" (Rom. 9:13) so that it might redound to His greater glory. But if human love is so great, the divine love is inconceivable. If the wicked can show so great gratitude, what ought to be said of God's goodness? Since the love is so immense, the union in which it has joined those who love must needs so surpass man's understanding that it cannot be likened to any similitude whatever.