The names of the months in the Bahá'í (Badí') calendar were given by the Báb, who drew them from the nineteen names of God invoked in a prayer said during the month of fasting in S̲h̲í'ih Islám.

Each of the days of the month is also given the name of one of the attributes of God. The names are the same as those of the nineteen months; thus, Naw-Rúz, the first day of the first month, would be considered the 'day of Bahá, of the month of Bahá'. If it fell on a Saturday, the first day of the Bahá'í week, it would be the 'day of Jalál'.