Indeed, the laws of God are like unto the ocean and the children of men as fish, did they but know it. However, in observing them one must exercise tact and wisdom... Since most people are feeble and far-removed from the purpose of God, therefore one must observe tact and prudence under all conditions, so that nothing might happen that could cause disturbance and dissension or raise clamour among the heedless. Verily, His bounty hath surpassed the whole universe and His bestowals encompassed all that dwell on earth. One must guide mankind to the ocean of true understanding in a spirit of love and tolerance. The Kitáb-i-Aqdas itself beareth eloquent testimony to the loving providence of God.
The principle governing this progressive application was enunciated in a letter written on behalf of Shoghi Effendi to a National Spiritual Assembly in 1935:
The laws revealed by Bahá’u’lláh in the Aqdas are, whenever practicable and not in direct conflict with the Civil Law of the land, absolutely binding on every believer or Bahá’í institution whether in the East or in the West. Certain ... laws should be regarded by all believers as universally and vitally applicable at the present time. Others have been formulated in anticipation of a state of society destined to emerge from the chaotic conditions that prevail today... What has not been formulated in the Aqdas, in addition to matters of detail and of secondary importance arising out of the application of the laws already formulated by Bahá’u’lláh, will have to be enacted by the Universal House of Justice. This body can supplement but never invalidate or modify in the least degree what has already been formulated by Bahá’u’lláh. Nor has the Guardian any right whatsoever to lessen the binding effect much less to abrogate the provisions of so fundamental and sacred a Book.