The Kitáb-i-Aqdas - The Most Holy Book
Index term: movements and prostrations, under Obligatory Prayer(s)
k10.
We have commanded you to pray and fast from the beginning of maturity; this is ordained by God, your Lord and the Lord of your forefathers. He hath exempted from this those who are weak from illness or age, as a bounty from His Presence, and He is the Forgiving, the Generous. God hath granted you leave to prostrate yourselves on any surface that is clean, for We have removed in this regard the limitation that had been laid down in the Book; God, indeed, hath knowledge of that whereof ye know naught. Let him that findeth no water for ablution repeat five times the words "In the Name of God, the Most Pure, the Most Pure", and then proceed to his devotions. Such is the command of the Lord of all worlds. In regions where the days and nights grow long, let times of prayer be gauged by clocks and other instruments that mark the passage of the hours. He, verily, is the Expounder, the Wise.
n4.
nine rak'ahs
A rak'ah is the recitation of specifically revealed verses accompanied by a prescribed set of genuflections and other movements.
The Obligatory Prayer originally enjoined by Bahá'u'lláh upon His followers consisted of nine rak'ahs. The precise nature of this prayer and the specific instructions for its recitation are unknown, as the prayer has been lost. (See note 9.)
In a Tablet commenting on the presently-binding Obligatory Prayers, 'Abdu'l-Bahá indicates that "in every word and movement of the Obligatory Prayer there are allusions, mysteries and a wisdom that man is unable to comprehend, and letters and scrolls cannot contain".
Shoghi Effendi explains that the few simple directions given by Bahá'u'lláh for the recital of certain prayers not only have a spiritual significance but that they also help the individual "to fully concentrate when praying and meditating".
n15.
God hath granted you leave to prostrate yourselves on any surface that is clean, for We have removed in this regard the limitation that had been laid down in the Book
The requirements of prayer in previous Dispensations have often included prostration. In the Arabic Bayán the Báb called upon the believers to lay their foreheads on surfaces of crystal when prostrating. Similarly, in Islám, certain restrictions are imposed with regard to the surface on which Muslims are permitted to prostrate. Bahá'u'lláh abrogates such restrictions and simply specifies "any surface that is clean".