Praised be Thou, O my God, that Thou hast ordained Naw-Rúz as a festival unto those who have observed the fast for love of Thee and abstained from all that is abhorrent unto Thee. Grant, O my Lord, that the fire of Thy love and the heat produced by the fast enjoined by Thee may inflame them in Thy Cause, and make them to be occupied with Thy praise and with remembrance of Thee.

(Baha'u'llah, Prayers and Meditations by Baha'u'llah, p. 67)

The Festival of Naw-Rúz falleth on the day that the sun entereth the sign of Aries, +F1 even should this occur no more than one minute before sunset.

(Baha'u'llah, The Kitab-i-Aqdas, p. 117)

Naw-Ruz is the first day of the New Year. It coincides with the spring equinox in the northern hemisphere, which usually occurs on 21 March. Bahá'u'lláh explains that this feast day is to be celebrated on whatever day the sun passes into the constellation of Aries (i.e. the vernal equinox), even should this occur one minute before sunset (Q and A 35). Hence Naw-Rúz could fall on 20, 21, or 22 March, depending on the time of the equinox.

(Baha'u'llah, The Kitab-i-Aqdas, p. 177)

In the Bahá’i calendar the first month of the year and the first day of each month are given the name "Bahá". The day of Bahá of the month of Bahá is thus the Bahá’i New Year, Naw-Rúz, which was ordained by the Báb as a festival and is here confirmed by Bahá'u'lláh

(Bahá'u'lláh, The Kitab-i-Aqdas, p. 225)

The Bahá’i New Year, Naw-Rúz, is astronomically fixed, coinciding with the March equinox

(Bahá'u'lláh, The Kitab-i-Aqdas, p. 228)

THESE are the days of Naw-Rúz. I am always thinking of those kind friends! I beg for each and all of you confirmations and assistance from the threshold of oneness, so that those gatherings may become ignited like unto candles

(Abd’u'l-Bahá, Tablets of the Divine Plan, p. 4)

These days are the days of Naw-Rúz, you have come to my mind and I am sending you this greeting for this glorious feast.

(Abd’u'l-Bahá, Tablets of the Divine Plan, p. 10)