Dom Prosper Guéranger: "
When the shepherd becomes a wolf, the first duty of the flock is to defend itself. It is usual and regular, no doubt, for doctrine to descend from the Bishops to the faithful, and those who are subject in the Faith are not to judge their superiors. But, in the treasure of Revelation there are essential doctrines which all Catholics, by the very fact of their title as such, are bound to know and defend. The principle is the same whether it be a question of belief or conduct, dogma or morals.

Treachery like that of Nestorius is rare in the Church, but it may happen that some pastors keep silence for one reason or another in circumstances when Religion itself is at stake. The true children of Holy Church at such times are those who walk by the light of their Baptism, not the cowardly souls who, under the specious pretext of submission to the powers that be, delay their opposition to the enemy in the hope of receiving instructions which are neither necessary nor desirable."