I would not expect to see Anselm or Aquinas supporting Penal Substitution, simply because they were Roman Catholics. Sacramentalism came into the Church very early, but took (perhaps) its biggest leap forward with the Cluniac Revival and the Hildebrandine Reforms of the 11th Century. Christ on the cross was diminished; Christ in the sacraments exalted.
Therefore there will be a tremendous difference in understanding between Anselm, Lombard and Aquinas on the one hand and Luther, Calvin and the Puritans on the other, simply because of their different understanding of Justification. If justification is a legal announcement by God that we are righteous on the grounds of Christ's satisfaction for sins, then He must have taken upon Himself God's curse upon sin and sinners, otherwise we must still be under it.
The reason that I have kept going with the issue of PSA is that it is so closely aligned with Justification. N.T. Wright, for example, who denies PST, also denies the Protestant understanding of justification and salvation by grace alone through faith alone (I cannot claim to have read all Wright voluminous works, but that is my understanding from what I have read). It is IMO inevitable. What Christ has not done for us we must do for ourselves or perish. But, praise God, Christ has done it all!![]()
Perhaps then there is misunderstanding that the Law did not demand retribution, but as Romans 3 states:
19Now we know that whatever the Law says, it speaks to those who are under the Law, so that every mouth may be closed and all the world may become accountable to God; 20because by the works of the Law no flesh will be justified in His sight; for through the Law comes the knowledge of sin.
21But now apart from the Law the righteousness of God has been manifested, being witnessed by the Law and the Prophets, 22even the righteousness of God through faith in Jesus Christ for all those who believe; for there is no distinction; 23for all have sinned and fall short of the glory of God, 24being justified as a gift by His grace through the redemption which is in Christ Jesus; 25whom God displayed publicly as a propitiation in His blood through faith. This was to demonstrate His righteousness, because in the forbearance of God He passed over the sins previously committed; 26for the demonstration, I say, of His righteousness at the present time, so that He would be just and the justifier of the one who has faith in Jesus.
Paul is not presenting that the law had some legal demand that was to be met by the suffering of Christ.21But now apart from the Law the righteousness of God has been manifested, being witnessed by the Law and the Prophets, 22even the righteousness of God through faith in Jesus Christ for all those who believe; for there is no distinction; 23for all have sinned and fall short of the glory of God, 24being justified as a gift by His grace through the redemption which is in Christ Jesus; 25whom God displayed publicly as a propitiation in His blood through faith. This was to demonstrate His righteousness, because in the forbearance of God He passed over the sins previously committed; 26for the demonstration, I say, of His righteousness at the present time, so that He would be just and the justifier of the one who has faith in Jesus.
Rather, Paul presents that the law had two significant purposes.
It makes man aware that they have sinned. That those "under the law" have not hope of redemption.
Next, it is that tool of God just as the prophets were to testify and witness to the righteousness of the Lord Jesus Christ.
To what end, what conclusion.
As Paul again states, that God may demonstrate through Christ being both the just (one) and the justifier (one who makes others just) God's ability and authority. That the Law is not demanding retribution or satisfaction, but is a witness along with all the prophets.
Too often, in my opinion, the "legal" demands are not properly matched with the statements of Scriptures.