The glorious Bab forbade association with Covenant-breakers.

The glorious Báb forbade association with Covenant-breakers. Bahá'u'lláh strictly forbade association with the Covenant-breakers, and even warned the friends against entering if possible a city where Covenant-breakers resided, as their poison polluted the entire area. 'Abdu'l-Bahá's teaching with regard to shunning and having no contact whatsoever with the Covenant-breakers is contained in hundreds of Tablets. The beloved Guardian forbade all association with Covenant-breakers and warned that their poison was so deadly, that it was not permissible to have even their literature in one's possession.

(Universal House of Justice, Ministry of the Custodians, pp. 235-236)