The famous Medieval abbot St. Bernard of Clairvaux (1090-1153) was one of the chief accusers to Peter Abelard who had espoused certain errors during his time. Abelard appealed to the bishop of Sens who held a local synod at which St. Bernard attended. Bernard then appealed to Pope Innocent II with the following request to examine Abelard and give an official condemnation to his errors.
“all the dangers and scandals that occur in the kingdom of God must be referred to the Holy See, but none more urgently than those which concern the faith. It is indeed just that any menace to the faith should be dealt with by the one 𝒘𝒉𝒐𝒔𝒆 𝒇𝒂𝒊𝒕𝒉 𝒄𝒂𝒏𝒏𝒐𝒕 𝒇𝒂𝒍𝒕𝒆𝒓. To whom else has it been said : 𝘐 𝘩𝘢𝘷𝘦 𝘱𝘳𝘢𝘺𝘦𝘥 𝘧𝘰𝘳 𝘵𝘩𝘦𝘦, 𝘗𝘦𝘵𝘦𝘳, 𝘵𝘩𝘢𝘵 𝘵𝘩𝘺 𝘧𝘢𝘪𝘵𝘩 fail 𝘯𝘰𝘵? The words that follow must apply to Peter’s successor… 𝘢𝘯𝘥 𝘵𝘩𝘰𝘶 𝘣𝘦𝘪𝘯𝘨 𝘰𝘯𝘤𝘦 𝘤𝘰𝘯𝘷𝘦𝘳𝘵𝘦𝘥, 𝘤𝘰𝘯𝘧𝘪𝘳𝘮 𝘵𝘩𝘦𝘺 𝘣𝘳𝘦𝘵𝘩𝘳𝘦𝘯. The time has come for you to acknowledge your primacy, to prove your zeal and to honour your ministry.𝑰𝒏 𝒕𝒉𝒊𝒔 𝒚𝒐𝒖 𝒘𝒊𝒍𝒍 𝒃𝒆 𝒇𝒖𝒍𝒇𝒊𝒍𝒍𝒊𝒏𝒈 𝑷𝒆𝒕𝒆𝒓’𝒔 𝒕𝒂𝒔𝒌, 𝒘𝒉𝒊𝒍𝒆 𝒚𝒐𝒖 𝒔𝒊𝒕 𝒐𝒏 𝒉𝒊𝒔 𝒕𝒉𝒓𝒐𝒏𝒆, 𝒊𝒇 𝒚𝒐𝒖 𝒄𝒐𝒏𝒇𝒊𝒓𝒎 𝒕𝒉𝒆 𝒇𝒂𝒊𝒕𝒉 𝒕𝒉𝒂𝒕 𝒗𝒂𝒄𝒊𝒍𝒍𝒂𝒕𝒆𝒔 𝒊𝒏 𝒕𝒉𝒆 𝒉𝒆𝒂𝒓𝒕𝒔 𝒐𝒇 𝑪𝒉𝒓𝒊𝒔𝒕𝒊𝒂𝒏𝒔, 𝒂𝒏𝒅 𝒑𝒖𝒏𝒊𝒔𝒉 𝒕𝒉𝒐𝒔𝒆 𝒘𝒉𝒐 𝒄𝒐𝒓𝒓𝒖𝒑𝒕 𝒕𝒉𝒆 𝒇𝒂𝒊𝒕𝒉, 𝒃𝒚 𝒎𝒆𝒂𝒏𝒔 𝒐𝒇 𝒚𝒐𝒖𝒓 𝒂𝒖𝒕𝒉𝒐𝒓𝒊𝒕𝒚.”
[𝘚𝘵. 𝘉𝘦𝘳𝘯𝘢𝘳𝘥. 𝘈𝘥. 𝘐𝘯𝘯𝘰𝘤. 𝘗. 𝘌𝘱. 𝘊𝘹𝘤𝘪.; 𝘌𝘯𝘨. 𝘛𝘳𝘢𝘯𝘴. 𝘚𝘵. 𝘉𝘦𝘳𝘯𝘢𝘳𝘥 𝘰𝘧 𝘊𝘭𝘢𝘪𝘳𝘷𝘢𝘶𝘹, 𝘵𝘳𝘢𝘯𝘴. 𝘎𝘦𝘰𝘧𝘧𝘳𝘦𝘺 𝘞𝘦𝘣𝘣 & 𝘈𝘥𝘳𝘪𝘢𝘯 𝘞𝘢𝘭𝘬𝘦𝘳 (𝘞𝘦𝘴𝘵𝘮𝘪𝘯𝘴𝘵𝘦𝘳, 𝘔𝘋: 𝘛𝘩𝘦 𝘕𝘦𝘸𝘮𝘢𝘯 𝘗𝘳𝘦𝘴𝘴, 1960), 102.]
As I was reading this letter (#191 in Bernard’s epistolary), I came to a couple observations.
The first was that what St. Bernard says here appears to be a full endorsement of what would later be called “Papal Infallibility”. That is confirmed simply by reading many other things that St. Bernard had written. However, once could find this kind of thing (even stronger) in the Church Fathers before the end of the 7th century, but Orthodox readers typically give it more of a “flowery hyperbole” kind of explanation so that the words being said are to be read as if going along with the elasticity of a musical note. In other words, 𝘯𝘰𝘵 𝘭𝘪𝘵𝘦𝘳𝘢𝘭. I really don’t think that could be used in reading St. Bernard who gives, more or less, the same kind of claim to Papal authority as Pope St. Agatho did in 680.
Secondly, I noticed here is that though Bernard gives a blanket claim to general immunity from error by “who faith cannot falter”, which matches what some of the ancient fathers comment on the prerogatives of the Apostolic See (cf. Leo, Gelasius, Hormisdas, et. al), he nevertheless implies that the Pope has to rise up and act in a certain way in order for the Petrine charism to take its effect. With that said, it doesn’t answer whether he would have believed that if Peter’s successor did rise up to the occasion of giving a teaching, it could be heretical content that gets put out. It seems he did not think so.