The Kitáb-i-Aqdas - The Most Holy Book
Index term: desires of the flesh, under Body
k2.
They whom God hath endued with insight will readily recognize that the precepts laid down by God constitute the highest means for the maintenance of order in the world and the security of its peoples. He that turneth away from them is accounted among the abject and foolish. We, verily, have commanded you to refuse the dictates of your evil passions and corrupt desires, and not to transgress the bounds which the Pen of the Most High hath fixed, for these are the breath of life unto all created things. The seas of Divine wisdom and Divine utterance have risen under the breath of the breeze of the All-Merciful. Hasten to drink your fill, O men of understanding! They that have violated the Covenant of God by breaking His commandments, and have turned back on their heels, these have erred grievously in the sight of God, the All-Possessing, the Most High.
k58.
Beware lest the desires of the flesh and of a corrupt inclination provoke divisions among you. Be ye as the fingers of one hand, the members of one body. Thus counselleth you the Pen of Revelation, if ye be of them that believe.
k64.
O people of the world! Follow not the promptings of the self, for it summoneth insistently to wickedness and lust; follow, rather, Him Who is the Possessor of all created things, Who biddeth you to show forth piety, and manifest the fear of God. He, verily, is independent of all His creatures. Take heed not to stir up mischief in the land after it hath been set in order. Whoso acteth in this way is not of Us, and We are quit of him. Such is the command which hath, through the power of truth, been made manifest from the heaven of Revelation.
n25.
We have enjoined upon you fasting during a brief period
Fasting and obligatory prayer constitute the two pillars that sustain the revealed Law of God. Bahá’u’lláh in one of His Tablets affirms that He has revealed the laws of obligatory prayer and fasting so that through them the believers may draw nigh unto God.
Shoghi Effendi indicates that the fasting period, which involves complete abstention from food and drink from sunrise till sunset, is

. . . essentially a period of meditation and prayer, of spiritual recuperation, during which the believer must strive to make the necessary readjustments in his inner life, and to refresh and reinvigorate the spiritual forces latent in his soul. Its significance and purpose are, therefore, fundamentally spiritual in character. Fasting is symbolic, and a reminder of abstinence from selfish and carnal desires.

Fasting is enjoined on all the believers once they attain the age of 15 and until they reach the age of 70 years.
A summary of the detailed provisions concerning the law of fasting and of the exemptions granted to certain categories of people is contained in the Synopsis and Codification, section IV.B.1.-6. For a discussion of the exemptions from fasting see notes 14, 20, 30 and 31.
The nineteen-day period of fasting coincides with the Bahá’í­ month of 'Alá', usually 2-20 March, immediately after the termination of the Intercalary Days (see notes 27 and 147), and is followed by the feast of Naw-Rúz (see note 26).