The Nineteen-Day Fast (2 March–20 March) is a nineteen-day period of the year, during which members of the Bahá'í Faith adhere to a sunrise-to-sunset fast. Along with obligatory prayer, it is one of the greatest obligations of a Bahá'í, and its chief purpose is spiritual; to reinvigorate the soul and bring the person closer to God. The fast was instituted by the Báb, and accepted by Bahá'u'lláh, the founder of the Bahá'í Faith, who stated its rules in his book of laws, the Kitáb-i-Aqdas.