But what will happen even if we do burn down the Jews synagogues and forbid them publicly to praise God, to pray, to teach, to utter God's name? They will still keep doing it in secret. If we know that they are doing this in secret, it is the same as if they were doing it publicly. for our knowledge of their secret doings and our toleration of them implies that they are not secret after all and thus our conscience is encumbered with it before God.
Martin Luther “On the Jews & Their Lies”, Gottfried & Fritz