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
Fasting during Ramadan dawn ("fajr"), and sunset ("maghrib"). Fasting is considered an act of deeply personal worship in which Muslims seek a raised level of closeness to God. During Ramadan, Muslims are also expected to put more effort into following the teachings of Islam by refraining from violence, anger, envy, greed, lust, angry/sarcastic retorts, gossip, and are meant to try to get along with each other better than normal. All obscene and irreligious stimuli are to be avoided as purity of both thought and action is important. Fasting during Ramadan is not obligatory for several groups for whom it would be excessively problematic,