The Kitáb-i-Aqdas - The Most Holy Book
Index term: Noon
k6.
n3, n4, n5, n6, n7, n8
We have enjoined obligatory prayer upon you, with nine rak’ahs, to be offered at noon and in the morning and the evening unto God, the Revealer of Verses. We have relieved you of a greater number, as a command in the Book of God. He, verily, is the Ordainer, the Omnipotent, the Unrestrained. When ye desire to perform this prayer, turn ye towards the Court of My Most Holy Presence, this Hallowed Spot that God hath made the Centre round which circle the Concourse on High, and which He hath decreed to be the Point of Adoration for the denizens of the Cities of Eternity, and the Source of Command unto all that are in heaven and on earth; and when the Sun of Truth and Utterance shall set, turn your faces towards the Spot that We have ordained for you. He, verily, is Almighty and Omniscient.
n5.
at noon and in the morning and the evening
Regarding the definition of the words “morning”, noon and “evening”, at which times the currently binding medium Obligatory Prayer is to be recited, Bahá’u’lláh has stated that these coincide with “sunrise, noon and sunset” (Q&A 83). He specifies that the “allowable times for Obligatory Prayers are from morning till noon, from noon till sunset, and from sunset till two hours thereafter”. Further, ‘Abdu’l-Bahá has stated that the morning Obligatory Prayer may be said as early as dawn.
The definition of noon as the period “from noon till sunset” applies to the recitation of the short Obligatory Prayer as well as the medium one.
n6.
We have relieved you of a greater number
The requirements for obligatory prayer called for in the Bábí­ and Islamic Dispensations were more demanding than those for the performance of the Obligatory Prayer consisting of nine rak’ahs that was prescribed in the Kitáb-i-Aqdas (see note 4).
In the Bayán, the Báb prescribed an Obligatory Prayer consisting of nineteen rak’ahs which was to be performed once in a twenty-four-hour period -- from noon of one day to noon of the next.
The Muslim prayer is recited five times a day, namely, in the early morning, at midday, in the afternoon and evening, and at night. While the number of rak’ahs varies according to the time of recitation, a total of seventeen rak’ahs are offered in the course of a day.
q83.
 
Question: Concerning the definition of "morning", "noon" and "evening".
Answer: These are sunrise, noon and sunset. The allowable times for Obligatory Prayers are from morning till noon, from noon till sunset, and from sunset till two hours thereafter. Authority is in the hand of God, the Bearer of the Two Names.