From the early days of the Faith, Bahá’u’lláh made provision for the breakers of the Covenant of God to be kept out of the community of the believers. In this Tablet, as in many others, Bahá’u’lláh exhorts the believers not to associate with these people. ‘Abdu’l-Bahá describes this action as similar to that of isolating an ill person who might otherwise spread a contagious disease to others.
(Revelation of Baha’u’llah volume four, by Adib Taherzadeh)
Source: Baha’i Texts