In an effort to clear up some spookiness that I’m hearing around these parts, I offer this quote from Ayres’s Nicaea and Its Legacy. E-Pro, this one’s for you:
One of the most important principles shared by pro-Nicenes is that whenever one of the divine persons acts, all are present, acting inseparably. In Chapter 15 I provide summary statements of the doctrine from Hilary, Ambrose, and Augustine: to them can be added this passage from Gregory of Nyssa:
“If… we understand that the operation of the Father, the Son, and the Holy Spirit is one, differing or varying in nothing, the oneness of their nature must needs be inferred from the identity of their operation. The Father, the Son, and the Holy Spirit alike give sanctification, and life, and light, and comfort, and all similar graces. And let no one attribute the power of sanctification in an especial sense to the Spirit, when he hears the saviour in the Gospel saying to the Father concerning his disciples, ‘Father, sanctify them in thy name.’… As we say that the operation of the Father, and of the Son, and the Holy Spirit is one, so we say that the Godhead is one…”
Understanding what is intended by this principle is, however, as complicated as understanding the consequences of any of the individual terminologies mentioned in the previous paragraph. Inseparable operation does not mean that the three persons are understood as merely co-operating in a given project. To begin to grasp the importance of the concept we need to turn to the doctrine of divine simplicity with which it is closely connected.
For pro-Nicenes God is non-composite: God has no parts, is incapable of division, and is not composed of a number of elements. In other words, God is simple. Most pro-Nicenes also add that God is infinite and is present everywhere, immediately and yet not as creatures are present to each other. As Christopher Stead has shown, however, ‘simplicity’ in early Christian hands is a concept deployed rather loosely. By the late fourth century speaking of the divine nature as simple is usually taken also to include a number of non-necessary corollaries, in particular that as simple God must be unique and incomprehensible. It will be important for the argument of this chapter, however, to show that although simplicity is not defined with great precision, it is used consistently. Earlier in the book I argued that during the fourth century the very ‘grammar’ of divinity was at issue. Within pro-Nicene theology we find a very clear if often implicit set of rules for such language. Pro-Nicenes assume the impossibility of there being degrees of divine existence, and they assume God to be the only truly simple reality. The generation of the Son and the breathing of the Spirit thus occur within the bounds of the divine simplicity. Because God is indivisible the persons cannot be understood to work as three-divided human persons at work. Linking divine simplicity and inseparability of operation draws us inexorably towards the persistent pro-Nicene assertion that the nature of God is unknowable.
~ Nicaea and its Legacy pg. 280-282
If I can explain this concept more simply (forgive me!), we can say it like this: Jesus IS the power, will, and wisdom of the Father. Admittedly this is Athanasian, but I think also Calvinian. Jesus’s will (the divine one) is not just in agreement in with the Father’s will, it is the Father’s will. The same goes for the Spirit. The one will of the divine nature is the Father’s, and thus the Son’s and the Spirit’s. This is in the Institutes too. I promise.
Furthermore, Jesus does not do the work of redemption as a man. This is completely wrongheaded. He is the Godman, and always acts as God, even as he acts as Godman. To say that he works as the second Adam purely as man is Nestorian, and plays right into the hands of critics who say that we sever the economic Trinity from the immanent Trinity. They are the same Trinity after all, differing in the “how,” not the “what” or “who.”
All theology is theology proper. Christology holds the center of theology proper. To obscure one is to obscure all.
Wedgewords 
Hello, thank you for your thoughts here. I’m exploring the doctrine of inseperable, and this post has proven invaluable.
I have one clarifying question about a Christological statement that you made toward the end though. What do you mean that Jesus does not accomplish salvation as a man? Is that an identity statement, or functional statement? This question might be more clear if I ask another question.
What do you think of Thomas Weinandy’s arguments about the incarnation? He affirms simplicity (and is chums with Dolezal), and he proposes a model of the incarnation that he calls a personal/existential model (drawing particularly on Cyril and Aquinas), in which one distinguishes the “who” of an identity from the manner of its expression. Thus the “who” of Jesus is always the divine who of God the Son, but the mode of His action within the incarnation is always as a man. In this way, He (God the Son) really acts and suffers as a man (and is not just God acting in man). Moreover, because the mode of the incarnation is not compositional, nothing of the divine attributes are lost (no kenosis, willing or otherwise). Rather, the One Person of God the Son, as God, comes to exist as man, and, in the incarnation, acts fully within the confines of that humanity (because to exist as a man is to adopt a human set of psychological faculties and act according to them).
He does this to be able to fully say that (1) it is really the Son of God that is man, (2) is really man that the Son of God is, and (3) the Son of God really is a man. This is by no means Nestorian. His whole goal is to most fully state the reality of the ontological union in the incarnation, and yet He says that Jesus acts as a man in the accomplishment of salvation. He says that even His miracles He does by the Spirit as man (though on the authority of His divine identity, I presume). He doesn’t lose sight of Jesus’ divinity. The Who is always God the Son, so insofar as Jesus humanly develops a self-identity, He develops the self-identity of being the Son of God through His relationship to the Father by the Spirit (Jesus knows Himself as Son because He knows the Father as Father).
That was a lot, but I hope it was somewhat coherent. I’d like to hear your response.