Commenting on Calvin's disagreements with Luther on the nature of the Eucharist, Kilian McDonnell noted that:
There is a Nestorian tendency in
Calvin as in Zwingli, though more pronounced in the latter. Calvin gave a
Nestorian emphasis to his Christology in his reaction against Luther and also
because of his desire to maintain the essential distinction of the two natures
and those properties special to each nature. Luther had taken the unity of the
person of Christ and proceeded through the use of communication of idioms to
extend the ubiquity of the divine person to the human nature of Christ. Calvin
took the immutability and incommunicability of the divinity and proceeded to
rather different Christological conclusions. In the heart of controversy lines
were drawn that might not otherwise have been drawn, and formulas were set up
which bear the imprint of the battle front. This must be kept in mind when judging
the Christological formulations of Calvin, especially his classical text, which
came to be known as the Extra Calvinisticum: “Even if the Word in his
immeasurable essence is united with the nature of man into one person, we do
not have to imagine that he was confined therein. Here is something marvelous:
the Son of God descended from heaven in such a way that, without leaving
heaven, he willed to be born in the virgin’s womb, to go about the earth, and
to hang upon the cross; yet he continuously filled the world even as he had
done from the beginning.” (Inst., II, 13, 4) The Christological dialectic
is clearly stated within a Platonic framework: the Godhead uncommitted in the Incarnation
remains the Godhead uncommitted; the Godhead unmixed, present everywhere, is
the Godhead undivided, present in his humanity.
. . .
We can see this tendency to separate
the two natures in Calvin’s doctrine of the redemptive value of the Passion. He
declared that the Passion of Christ was, in itself, of no particular value or
efficacy; what value the Passion had was bestowed upon it by the divine will
when it accepted the Passion as sufficient. It was this acceptance which gave
the Passion its redemptive value. “Apart from God’s pleasure Christ could not
merit anything; but did so because he had been appointed to appease God’s wrath
with his sacrifice, and to blot out our transgressions with his obedience. To
sum up: inasmuch as Christ’s merit depends upon God’s grace alone, which
ordained this manner of salvation for us, it is just as properly opposed to all
human righteousness as God’s grace is.” (Inst., II, 17, 1) The accent on
the will of God and on the acceptation divina makes one wonder to what
degree Calvin is here indebted to the nominalist tradition.
The doctrine of the ontological union of
the two natures would therefore be suspect in Calvin’s mind as a mixing of the
natures, although a union of natures is not necessarily a mixing and can be
achieved without losing the integrity of either nature. Calvin’s thought
processes concentrated rather on the indivisible unity of the person of Christ.
By reason of the indivisible unity of the person of Christ one attributes to
human nature what belongs to the divine nature, and vice versa. It should be
note that Calvin speaks of an omnipresence of God through his Godhead or
divinity, but he also speaks of the omnipresence of the person of the God-mean,
the Mediator: “Although Christ, who is God and man, mediator between God and
man, whole and undivided as he is, fills heaven and earth, but with respect to
his flesh, he is only in heaven.” (CR 9:246) For Calvin, the communication of
idioms is not to be found in the ontological union of two integral natures, but
exclusively in the office of Christ as the Mediator: “Insofar as he is God, he
cannot increase in anything, and does all things for his own sake; nothing is
hidden from him; he does all things according to the decision of his will, and
can be neither seen nor handled. Yet he does not ascribe these qualities solely
to his human nature, but takes upon himself as being in harmony with the person
of the Mediator.” (Inst., II, 14, 2)
Calvin gives a further restriction. He
considers the communication of idioms in the Mediator only in relationship to
the saving work of that Mediator: “Until he comes forth as judge of the world,
Christ will therefore reign, joining us to the Father as the measure of our
weakness permits. But when as partakers in heavenly glory we shall see God as
he is, Christ, having then discharged the office of Mediator, will cease to be
the ambassador of his Father, and will be satisfied with that glory which he
enjoyed before the creation of the world . . . He [Christ] then returns the
lordship to his Father so that—far from diminishing his own majesty—it may
shine all the more brightly. Then, also, God shall cease to be the Head of
Christ, for Christ’s own deity will shine of itself, though as yet it is
covered by a veil.” (ibid., 14, 3) (Kilian McDonnell, John Calvin,
the Church and the Eucharist [Princeton: Princeton University Press, 1967],
213-14, 215-17)