O ye the faithful loved ones of ‘Abdu’l-Baha! It is incumbent upon you to take the greatest care of Shoghi Effendi, the twig that hath branched from and the fruit given forth by the two hallowed and Divine Lote-Trees, that no dust of despondency and sorrow may stain his radiant nature, that day by day he may wax greater in happiness, in joy and spirituality, and may grow to become even as a fruitful tree.
For he is, after ‘Abdu’l-Baha, the Guardian of the Cause of God, the Afnan, the Hands (pillars) of the Cause and the beloved of the Lord must obey him and turn unto him. He that obeyeth him not, hath not obeyed God; he that turneth away from him, hath turned away from God and he that denieth him, hath denied the True One. Beware lest anyone falsely interpret these words, and like unto them that have broken the Covenant after the Day of Ascension (of Baha’u’llah) advance a pretext, raise the standard of revolt, wax stubborn and open wide the door of false interpretation. To none is given the right to put forth his own opinion or express his particular conviction. All must seek guidance and turn unto the Center of the Cause and the House of Justice. And he that turneth unto whatsoever else is indeed in grievous error.
‘Abdu’l-Bahá, Will and Testament of `Abdu’l-Bahá, paragraph 54-55