Qur'an: 1 day = 1,000 years. Babi: 1 day = 1 year. Bahá'í: 30 days = ?

"Concerning the passage in the 'Dispensation of Bahá'u'lláh' in which the Guardian quotes Abdu'l-Bahá's interpretation of the prophecy referring to the times when the sun would stand still in the heavens, he wishes me to explain that the days referred to in this prophecy have to be reckoned differently. In the Sacred Scripture of various religions there are to be found frequent references to days, but these have been considered as indicating different periods of time, as for instance in the Qur'an a day is reckoned as one thousand years. The first ten days in the above-mentioned prophecy represent each a century, making thus a total of one thousand lunar years. As to the twenty days referring to the Babi Dispensation, each of them represents only one lunar year, the total of twenty years marking the duration of the Revelation of the Bab. The thirty days in the last Dispensation should not be reckoned numerically, but should be considered as symbolizing the incomparable greatness of the Bahá'í Revelation which, though not final, is nonetheless thus far the fullest revelation of God to man. From a physical point of view, the thirty days represent the maximum time taken by the sun to pass through a sign of the zodiac. They thus represent a culminating point in the evolution of this star. So also from a spiritual standpoint these thirty days should be viewed as indicating the highest, though not the final, stage in the spiritual evolution of mankind."

(From a letter written on behalf of the Guardian to the National Spiritual Assembly of the United States and Canada, August 7, 1934: Bahá'í News, No. 87, September 1934, p. 1)