The twofold nature of a believer’s task – the Guardian explains

Let every believer, desirous to witness the swift and healthy progress of the Cause of God, realize the twofold nature of his task. Let him first turn his eyes inwardly and search his own heart and satisfy himself that in his relations with his fellow-believers, irrespective of colour and class, he is proving himself increasingly loyal to the spirit of his beloved Faith. Assured and content that he is exerting his utmost in a conscious effort to approach nearer every day the lofty station to which his gracious Master summons him, let him turn to his second task, and, with befitting confidence and vigour, assail the devastating power of those forces which in his own heart he has already succeeded in subduing. Fully alive to the unfailing efficacy of the power of Bahá'u'lláh, and armed with the essential weapons of wise restraint and inflexible resolve, let him wage a constant fight against the inherited tendencies, the corruptive instincts, the fluctuating fashions, the false pretences of the society in which he lives and moves. (Shoghi Effendi, in a letter dated 12 April 1927 to the National Spiritual Assembly of the United States and Canada, published in "Bahá'í Administration: Selected Messages 1922-1932"; ; The Compilation of Compilations, vol. I, Excellence in All Things)