It is a common objection to suppose that Calvinism suffers from an ancient heresy that denied that Jesus had two wills or that merely one of the wills are not equally involved in Christ’s life. This is how the Orthodox defines the ancient heresy:

The background to the Sixth Ecumenical Council was the struggle with the heresies of Monoenergism and Monothelitism. The Monothelites had asserted that while Christ possessed two natures, He only had one will. The Monoenergists, on the other hand, maintained that Christ was animated by only one ‘energy.’

Concerned that both these positions undermined Chalcedonian Christology by implying Monophysitism (the belief that Christ has only a divine nature and not a human nature, which would be a species of Docetism), the council condemned both positions. Drawing on the theology of St. Maximus the Confessor (580-662), the council provided a framework for understanding the relationship between the human and the divine, and by extension the spiritual and the material.

Against the Monoenergists, the Orthodox Christians at Chalcedon affirmed that Jesus acted through two energies: the divine and the human. Against the Monothelites, they maintained that if Christ is truly man and truly God, then He must have two wills: a human will and a divine will. The two wills work together synergistically, even as human beings are called to co-operate our human will with the energies of God. Thus, the doctrine affirmed by the Sixth Ecumenical Council was known as Dyoenergism, meaning “two energies.”

https://robinmarkphillips.com/calvinisms-christology-problem/

Here are his reasons for why it is applicable to Calvinism:

It began to dawn on me that the Monergism of Calvinism seemed to be driven by many of the same concerns that animated the ancient Monoenergists, for both tended to treat the divine and the human as if they are two sides in a zero-sum transaction. Soteriological Monergism, no less than the heresy of Monoenergism, sees the divine and the human competing for the same space, and both want to give the divine all the pieces of the pie.

This becomes clear when we address the crucial question that Calvinism never seems to squarely face, namely, whether Christ’s human will was predestined to obey the Father, or whether His human will remained exempt from the predestination applied to the rest of the human race. …

Once you say that Christ’s human will was subordinated to, and irresistibly moved by, the divine will, then you have essentially embraced a version of Monothelitism. For what very few Calvinists realize is that Monothelitism was far more than merely a denial of the natural human will in Christ, which is why some Monothelites were even happy to acknowledge that Christ had two wills. Rather, it is clear from Saint Maximus’s The Disputation With Pyrrhus that their heresy involved the notion that even if Christ did possess both a divine and a human will, the human will was only a type of instrument that was used by the divine in a determining fashion. As Schonborn points out, Monothelitism was “characterized by its incapacity to view the impeccability of Christ other than as a passive determination of the human nature by the divine nature…” (Schonborn, cited in Farrell, Free Choice in St. Maximus the Confessor, p. 192). Similarly, when Thomas Aquinas was describing the Monothelite heresy in his Summa Contra Gentiles, he said that “they saw the human will in Christ ordered entirely beneath the divine will so that Christ willed nothing with his human will except that which the divine will disposed him to will.”

As this suggests, even when they could grant two wills, Monothelitism was characterized by the belief that there was only one activity or “energy” operative in Christ since the humanity of Christ was essentially a tool that was subordinated to, and determined by, the divine.

The first problem with the argument here is that it simply ignores the fact that the Biblical writers viewed the life of Christ as predestined. I am not surprised that an Orthodox person would have problems with the testimony of John, Luke, and other Biblical figures. There are several places that speak of predestination in regards to Christ (or at least allusions to it):

Mark 14

⁴¹ And He *came the third time, and *said to them, “Are you still sleeping and resting? That is enough. The hour has come; behold, the Son of Man is being betrayed into the hands of sinners.

John 7

³⁰ Therefore they sought to take Him; but no one laid a hand on Him, because His hour had not yet come.

Acts 2

²² “Men of Israel, listen to these words: Jesus the Nazarene, a Man attested to you by God with miracles and wonders and signs which God performed through Him in your midst, just as you yourselves know— ²³ this Man, delivered over by the predetermined plan and foreknowledge of God, you nailed to a cross by the hands of godless men and put Him to death. ²⁴ But God raised Him from the dead, putting an end to the agony of death, since it was impossible for Him to be held in its power. ²⁵ For David says of Him,

Acts 4

²³ When they had been released, they went to their own companions and reported everything that the chief priests and the elders had said to them. ²⁴ And when they heard this, they raised their voices to God with one mind and said, “Lord, it is You who made the heaven and the earth and the sea, and everything that is in them, ²⁵ who by the Holy Spirit, through the mouth of our father David Your servant, said,

²⁷ For truly in this city there were gathered together against Your holy servant Jesus, whom You anointed, both Herod and Pontius Pilate, along with the Gentiles and the peoples of Israel, ²⁸ to do whatever Your hand and purpose predestined to occur. ²⁹ And now, Lord, look at their threats, and grant it to Your bond-servants to speak Your word with all confidence, ³⁰ while You extend Your hand to heal, and signs and wonders take place through the name of Your holy servant Jesus.” ³¹ And when they had prayed, the place where they had gathered together was shaken, and they were all filled with the Holy Spirit and began to speak the word of God with boldness.

In the Acts passage, we have this tied with the OT passage showing the Divine intention has been there since the beginning. Luke just states that these men and events have been predestined by the God of Israel. In the Gospels, this idea gets put in other terms such as “the hour”. This leaves our Orthodox friend in a dilemma. Suppose that the Orthodox says that these events were predestined, but that doesn’t entail God predestines everything. The objector has the problem that they now have conceded that God can destine things by his will and not reduce things to “one energy” or “one will”.

Furthermore, you may read this article a hundred times and still never find an argument that Divine Predestination (in the strong predestinarian sense) is inconsistent with human freedom. That God’s causation renders human causation void is merely assumed (that it must be subsumed). The author never provides an argument to such a conclusion.

There is also a mistake on the part of the author in regards to impeccability. One does not need to explain Christ’s impeccability by reducing it to divine causation. They merely have to suppose that it is a precondition of impeccability, but other reasons also exist to explain why it is the case.

There is also a historical argument to be had surrounding the Third Council of Constantinople. He supposes that one has to accept Maximus’ theory of the will in order to affirm the Council, but the argument for that doesn’t seem to be there either. It seems the general ideas can be affirmed by Calvinists:

We declare that in Christ there are two natural wills and two natural energies, without division, without change, without separation, without confusion, according to the teaching of the holy fathers. And these two natural wills are not contrary to one another (God forbid!), as the ungodly heretics assert, but His human will follows His divine will, not resisting or reluctant, but subject to His divine and all-powerful will … We glorify two natural energies, that is, a divine energy and a human energy, without division, without change, without confusion, without separation, in the same Lord Jesus Christ, our true God.

Without Calvinism being the context of the debate it is difficult and nearly anachronistic to think it is an outright condemnation of Calvinism. Suppose that I grant that the interpretation he is providing is correct. He would have to push the argument as to why we can’t have the beneficial Christology without determinism? I would simply reject the Council’s position and de, and the argument for the contradiction.

In this article, he states this while setting up his dilemma:

Saying that Christ is exempt from Divine predestination also seems to suggest, at least by implication, that some version of libertarian freedom may not be an intrinsically incoherent concept as Calvinists will frequently assert.

I would just say that we are awaiting this model of libertarianism that is coherent in any respect. We have objections to this view of freedom that can’t be taken lightly.

The Problem of Arbitrary Choice and Inerrancy:

http://spirited-tech.com/2018/12/27/bruce-ware-on-freewill/

http://spirited-tech.com/2018/02/01/inerrancy-is-it-a-matter-of-luck/

http://spirited-tech.com/2018/12/27/why-im-not-an-open-theist/

Aseity vs LFW:

http://spirited-tech.com/2019/10/01/the-thibodaux-saga/