Jonathan Edwards and John Piper on the atonement

I’ve been reading Jonathan Edwards and John Piper on the atonement lately.  Both (naturally because Piper emulates Edwards on most theological issues) highlight what has traditionally been called the “rectoral” dimension of the atonement.  That is, the atonement was primarily about preserving and demonstrating God’s moral governance of the world.

Now, the irony is that this view of the atonement is traditionally associated with Arminianism.  (I have a chapter on that in my book Arminian Theology: Myths and Realities.)  In relation to Arminianism it is known as the “governmental theory of the atonement.”  Not all Arminians hold it.  For example, Wesley did not. 

Both Edwards and Piper seem to emphasize the idea that Christ had to die to justify or vindicate God’s righteousness in saving the elect.  The idea in traditional moral governmental theory (going back to Hugo Grotius–one of the original Remonstrants in Holland) is that Christ suffered the equivalent punishment for sins.  That is, he did not suffer your punishment or mine but a equivalent one to ours.  The purpose was to demonstrate God’s justice with regard to sin and vindicate God’s forgiveness of sinners as righteous.

What I have not been able to find is where Edwards or Piper explicitly say that Christ suffered every individual elect person’s punishment (the traditional penal substitution theory). 

If you know of some place in their writings where they say that explicitly I would very much like to know it. 

Why does it matter?  Because many Calvinists accuse Arminians of denying the orthodox doctrine of the atonement (which is assumed ot be the penal substitution theory).  Of course, many Arminians including Arminius himself (!) held to it.  During the 19th and 20th centuries, however, Grotius’ theory enjoyed a renaissance among Arminian scholars (e.g., John Miley and H. Orton Wiley).

I think it would be interesting and ironic if Edwards and/or Piper emphasize the rectoral nature of the atonement without equally asserting the penal nature of the atonement.  But, I’m not drawing any conclusions just yet.  I would like to know if anyone knows some place in Edwards’ or Piper’s writings where one or both clearly and unequivocally affirm the penal substitution view of the atonement.  Thanks.