April 19

As to the significance of that Declaration let Bahá’u’lláh Himself reveal to us its import. Acclaiming that historic occasion as the “Most Great Festival,” the “King of Festivals,” the “Festival of God,” He has, in His Kitáb-i-Aqdas, characterized it as the Day whereon “all created things were immersed in the sea of purification,” whilst in one of His specific Tablets, He has referred to it as the Day whereon “the breezes of forgiveness were wafted over the entire creation.” 
(Shoghi Effendi, ‘God Passes By’)