“Recite ye the verses of God every morn and eventide.” (Bahá’u’lláh, ‘The Kitáb-i-Aqdas’)

May 10

As regards thine assertions about the beginning of creation, this is a matter on which conceptions vary by reason of the divergences in men's thoughts and opinions. Wert thou to assert that it hath ever existed and shall continue to exist, it would be true; or wert thou to affirm the same concept as is mentioned in the sacred Scriptures, no doubt would there be about it, for it hath been revealed by God, the Lord of the worlds. Indeed He was a hidden treasure. This is a station that can never be described nor even alluded to. And in the station of 'I did wish to make Myself known', God was, and His creation had ever existed beneath His shelter from the beginning that hath no beginning, apart from its being preceded by a Firstness which cannot be regarded as firstness and originated by a Cause inscrutable even unto all men of learning.

That which hath been in existence had existed before, but not in the form thou seest today. The world of existence came into being through the heat generated from the interaction between the active force and that which is its recipient. These two are the same, yet they are different. Thus doth the Great Announcement inform thee about this glorious structure. Such as communicate the generating influence and such as receive its impact are indeed created through the irresistible Word of God which is the Cause of the entire creation, while all else besides His Word are but the creatures and the effects thereof. Verily thy Lord is the Expounder, the All-Wise. 
(Baha'u'llah, Tablets of Baha'u'llah revealed after the Kitab-i-Aqdas)