His fears are rather for those friends who, due to their insufficient realization of the divine power that mysteriously operates in the Faith, are prone to look at such developments as constituting the death-knell of the Cause … he has always stressed the fact, and he wishes you to do the same in all your conversations and correspondence … that the Cause is bound sooner or later to suffer from all kinds of attacks and persecutions, that these in fact constitute the life-blood of its institutions, and as such constitute an inseparable and intrinsic part of its development and growth. Trials and tribulations, as Bahá’u’lláh says, are the oil that feed the lamp of the Cause, and are indeed blessings in disguise. The friends should therefore be confident that all these attacks to which the Cause is now subjected in ... are a necessary part of the development of the Cause, and that their outcome would be beneficial to its best interests.
(Shoghi Effendi, The Compilation of Compilations vol. I, p. 148-149)
The recent articles attacking the Cause are a sign that its influence is sufficiently felt to be feared—a great compliment to the progress you are making in spreading the message!
(Shoghi Effendi, Letters from the Guardian to Australia and New Zealand, p. 59)