Naw Rúz greetings from South Africa

Praised be Thou, O my God, that Thou hast ordained Naw-Ruz as a festival unto those who have observed the fast for love of Thee and abstained from all that is abhorrent unto Thee

Bahá'u'lláh, Prayers and Meditations by Bahá'u'lláh, p. 67

Naw-Ruz itself was originally a Zoroastrian religious festival, but gradually its Zoroastrian connotation has almost been forgotten. Iranians, even after their conversion to Islam, have been observing it as a national festival. Now Naw-Ruz has become a Bahá'í Holy Day and is being observed throughout the world....

Compilations, Lights of Guidance, p. 553

It is a lovely day, the sun shines brightly upon the earth, giving light and warmth to all creatures. The Sun of Truth is also shining, giving light and warmth to the souls of men. The sun is the life-giver to the physical bodies of all creatures upon earth; without its warmth their growth would be stunted, their development would be arrested, they would decay and die. Even so do the souls of men need the Sun of Truth to shed its rays upon their souls, to develop them, to educate and encourage them. As the sun is to the body of a man so is the Sun of Truth to his soul.

'Abdu'l-Bahá, Paris Talks, p. 30

... This sacred day, when the sun illumines equally, is called the equinox, and the equinox is the symbol of the Manifestation of God. The Sun of Truth rises on the horizon of Divine Mercy and sends forth its rays. This day is consecrated to commemorate it...

Talk by 'Abdu'l Bahá, March 21, 1913: Star of the West, Vol. 5, No. 1, p. 4
Compilations, Lights of Guidance, p. 301