The summary:
As Christ is sinless, the Father did not compel Him to die but rather, Christ wished to die on His own free will.
God did not, therefore, compel Christ to die; but he suffered death of his own will, not yielding up his life as an act of obedience, but on account of his obedience in maintaining holiness
As a figure of speech, it can be said that the Father moved Christ to His death, as the Father gave the Son the gift of obedience to the Father's will. However, the way in which the Father moved Christ did not overcome Christ's free will.
... in this drawing or impelling it is not to be understood that there is any constraint, but a free and grateful clinging to the holy will which has been given. If then it cannot be denied that the Father drew or moved the Son to death by giving him that will; who does not see that, in the same manner, he gave him commandment to endure death of his own accord and to take the cup, which he freely drank. And if it is right to say that the Son spared not himself, but gave himself for us of his own will, who will deny that it is right to say that the Father, of whom he had this will, did not spare him but gave him up for us, and desired his death? In this way, also, by following the will received from the Father invariably, and of his own accord, the Son became obedient to Him, even unto death; and learned obedience from the things which he suffered; that is, be learned how great was the work to be accomplished by obedience.
Now we understand how the will of the Father and of the Son interacted in the Incarnation and the Passion. In the next installment we will inquire into their necessity: The question which still troubles us is, how the death of the Son can be proved reasonable and necessary.
Hmmm...it sounds as if what is being said here is that God the Father plan was based upon what the Son was willing to do of His own will. Is this correct?
Thank you for pinging me to these, Alex. I will be interested to see the answer to this. I'd also like to know what the view is on the operation of the two wills of Christ. In this installment it appears to concentrate on Christ's human will. Probably most Christians say some version of "the wills worked in harmony", but I'm not sure how that actually manifested itself. For example, when Jesus contemplated the cup, did He really defer to His own divine will, or did He wholly and separately defer to the Father's will? Or, if it's all the same, does it still count as an exercise of free will that we can identify with?