It was not the RCC that came up with the Penal Substitution Theory of Atonement. Whoever told you that was wrong. It was the Reformers who came up with the theory in an attempt to reform RCC doctrine (the RCC held a "satisfaction" view focused on merit). The RCC is the Mother of Penal Substitution Theory as the Theory was birthed in the Reformation.Someone else came up with this claim an another thread. I asked him which Synod or which Papal decree he was referring to and he went strangely quiet. So perhaps you can help me.
I find the claim rather hard to believe since many of the Church Fathers support the Doctrine of Penal Substitution in their writings.
It does rather seem to me that it is your belief that is Roman Catholic. You start off by saying that you believe in nothing but Scripture, and then, when your views are shown to be wrong, you appeal to the Church fathers. I have debated a few Roman Catholics over the years, and that tends to be their tactic.
BTW, Infirmity is not spelled 'infirmaty.' Just saying.
I use my phone mostly. My phone can't spell. I usually catch "Hod" instead of "God", but really font care about the rest. I give the phone a little room.