The doctrine of the covenant of redemption seems to imply a distinct plan for each member of the Trinity. So what are we to think of it?
For it seems to be forgotten that the Father, the Son, and the Spirit are the three persons of the one Triune God, in utter harmony and unity, in the life of which there is no moment in which their minds, having previously been in a state of indecision, come to be made up. For they have an eternal, timeless, existence. In any case this state of affairs could only be so if the two or three persons had separate divine minds, and if there were moments in eternity when agreements were fashioned. But to move in that direction is, as I say, to court tritheism, and a social trinitarianism, in which the divinity of the Trinity refers not to one divine essence, but to a nature shared among the persons of the Trinity, like you and I and Barak Obama share human nature. And (unless we throw a spanner in the works) it is to to take a step towards divine temporality in which God in three persons enjoys not an eternal life, but an unending life.
This [pre-temporal] counsel is Trinitarian, as is clear from that chapter [III] and the preceding one [II] on the Trinity. However, to describe the relations of the three persons in the Trinity as a covenant, or to affirm that there was a need for them to enter into covenantal - even contractual - arrangements is to open the door to heresy. The will of the Trinity is one; the works of the Trinity are indivisible. (236)
The will is a natural property [ie the property of the nature of what possesses the will] and therefore in the divine essence it is but one. The Father, Son, and Spirit, have not distinct wills. They are one God, and God’s will is one, as being an essential property of his nature; and therefore are there two wills in the one person of Christ, whereas there is but one will in the three persons of the Trinity. How, then, can it be said that the will of the Father and the will of the Son did concur distinctly in the making of this covenant? (87)Good question. Here’s how he answers it. First, he notes the reciprocal relations of the wills in the persons of the Trinity, in which their essential acts are involved, their acts of understanding, love and the like, the one for the other, due to their mutual indwelling, their perichoretic relationship. The one will of God is peculiarly (i.e. specially, or distinctly) attributed to each person of God in this indwelling. It is on this basis, that if indwelling is OK then 'federal transactions' are, that Owen argues. So the will of God as it is the will of the Son is distinct from the will of God as it is the will of the Father. It is 'the distinct application of the same will unto its distinct acts in the persons of the Father and the Son.' (88) So the persons of the Trinity do not have distinct wills but one will which has 'distinct applications'. And so in the matter of the covenant of redemption.
And in this respect the covenant whereof we treat differeth from a pure decree; for from these distinct actings of the will of God in the Father and the Son there doth arise a new habitude or relation, which is not natural or necessary unto these, but freely taken on them. And by virtue hereof were all believers saved from the foundation of the world, upon the account of the interposition of the Son of God antecedently unto his exhibition in the flesh; for hence was he esteemed to have done and suffered what he had undertaken so to do and which, through faith, was imputed to them that did believe. (88)
The idea seems to be that if we count acts by their objects then we have distinct application of the will; say that choosing the elect is one object then being the Saviour of the elect is another object. But if we count acts by their sources then since in each case this is God's will then it must be one will. Yet it looks for all the world as if what Owen calls a 'distinct application' of a will is itself an act of the will. What else could it be? But then, an act of whose will?
Yet Owen may mean something different. Can the will of the Son to do the Father's will be the same willing as that of the Father that the Son do the Father's will, but each expressive of a different habitude, one a filial habitude, the other a paternal habitude? Or the will of the Father to give the Son a bride be the same as that of the will of the Son to be given a bride by the Father? Is that what Owen means? (That is, for every voluntary act of one of the Persons, there are corresponding 'chiming' voluntary acts on the parts of the other persons). If so, he is home and dry. Except that there does not seem much that is bilateral (or trilateral) in such states of affairs, as their respective roles in the covenant of redemption requires.
As Owen earlier says, ‘God’s will be one, as being an essential property of his nature?....Father, Son and Spirit have not distinct wills’. Is he not running into obscurities, even contradictions, in pursuit of a coherent account of an eternal covenant of redemption? Does he not wobble over the question, does the Triune God have one will or not? The going certainly gets pretty treacly, doesn't it? Is not the wiser course to call off this particular chase and instead to think of the covenantal language used of the Son in Scripture as applying not to an eternal pactum but to the Son's incarnate life as the Christ?
Maybe, in the spirit of William of Ockham, we should not multiply plans unnecessarily; that is, divine plans. (There's not much we can do about human plans.) And stick to 'the plan of salvation'.