Nineteen-Day Fast to be the one foretold by the Báb, accepted the fast, but altered many of its details and regulations. The Bahá'í fast resembles fasting practices of several other religions. Lent is a period of fasting for Christians, Yom Kippur and many other holidays for Jews, and the fast of Ramadan is practiced by Muslims. The Bahá'í fasting most resembles the fast of Ramadan, except that the period of fasting is defined as a fixed Bahá'í month, whereas Muslims fast during a lunar month, whose specific Gregorian dates vary from year to year. Bahá'u'lláh established the guidelines of the fast in
Ramadan or dryness. Fasting is fard (obligatory) for adult Muslims, except those who are suffering from an illness, travelling, are elderly, pregnant, breastfeeding, diabetic, chronically ill or menstruating. Fasting the month of Ramadan was made obligatory (wājib) during the month of Sha'ban, in the second year after the Muslims migrated from Mecca to Medina. Fatwas have been issued declaring that Muslims who live in regions with a natural phenomenon such as the midnight sun or polar night should follow the timetable of Mecca, but the more commonly accepted opinion is that Muslims in those areas should follow the timetable of the