The Kitáb-i-Aqdas - The Most Holy Book
Index term: Intercalary days (Ayyám-i-Há)
k16.
O Pen of the Most High! Say: O people of the world! We have enjoined upon you fasting during a brief period, and at its close have designated for you Naw-Rúz as a feast. Thus hath the Day-Star of Utterance shone forth above the horizon of the Book as decreed by Him Who is the Lord of the beginning and the end. Let the days in excess of the months be placed before the month of fasting. We have ordained that these, amid all nights and days, shall be the manifestations of the letter Há, and thus they have not been bounded by the limits of the year and its months. It behoveth the people of Bahá, throughout these days, to provide good cheer for themselves, their kindred and, beyond them, the poor and needy, and with joy and exultation to hail and glorify their Lord, to sing His praise and magnify His Name; and when they end -- these days of giving that precede the season of restraint -- let them enter upon the Fast. Thus hath it been ordained by Him Who is the Lord of all mankind. The traveller, the ailing, those who are with child or giving suck, are not bound by the Fast; they have been exempted by God as a token of His grace. He, verily, is the Almighty, the Most Generous.
n29.
these days of giving that precede the season of restraint
Bahá'u'lláh enjoined upon His followers to devote these days to feasting, rejoicing and charity. In a letter written on Shoghi Effendi's behalf it is explained that "the intercalary days are specially set aside for hospitality, the giving of gifts, etc.".
n147.
The number of months in a year, appointed in the Book of God, is nineteen.
The Bahá'í year, in accordance with the Badí' calendar, consists of nineteen months of nineteen days each, with the addition of certain intercalary days (four in an ordinary year and five in a leap year) between the eighteenth and nineteenth months in order to adjust the calendar to the solar year. The Báb named the months after certain attributes of God. The Bahá'í New Year, Naw-Rúz, is astronomically fixed, coinciding with the March equinox (see note 26). For further details, including the names of the days of the week and the months, see the section on the Bahá'í calendar in The Bahá'í World, volume XVIII.