To the revered lord and dearest father, Master Guido, by grace of God cardinal priest of the holy Roman Church, Bernard, styled abbot of Clairvaux, not to turn aside to the right hand nor to the left.

I do you wrong if I were to suppose that you love someone in such a way that you love his errors equally with him. For anyone who loves someone like that does not yet know how one should love him. Affection like that is ‘earthly, sensual, devilish’, harmful to lover and loved alike. Others may make judgements about others as they will: I can still not make a judgement about you that is not close neighbour to reason, that does not toe the line of equity. Some judge first and look for proof later: I shall not judge if a drink is sweet or bitter before I taste it. Master Peter introduces ‘profane novelties of words’ and meaning in his books; he disputes about the faith against the faith, he assails the law with the words of the law. He sees nothing through a glass or in a dark manner, but gazes on everything face to face, ‘walking in great’ and ‘wonderful matters above him’. It would be better for him if, in accordance with the title of his own book, he got to know himself, and did not go beyond his measure ‘but was wise unto sobriety’. I do not accuse him to the Father: he has his own book to accuse him, in which he was ill pleased. When he speaks of the Trinity, he savours of Arius; when of grace, he savours of Pelagius; when of the person of Christ, he savours of Nestorius. I do not presume on your fair-mindedness if I have asked you for a long time not to prefer anyone to Christ in the cause of Christ. But know this, that it is expedient for you, to whom ‘power is given by the Lord’, it is expedient to the Church of Christ, it is expedient to that man himself, that silence be imposed on him ‘whose mouth is full of cursing and of bitterness and of deceit’.