May 6

As to the attributes and perfections such as will, knowledge, power and other ancient attributes that we ascribe to that Divine Reality, these are the signs that reflect the existence of beings in the visible plane and not the absolute perfections of the Divine Essence that cannot be comprehended. For instance, as we consider created things we observe infinite perfections, and the created things being in the utmost regularity and perfection we infer that the Ancient Power on whom dependeth the existence of these beings, cannot be ignorant; thus we say He is All-Knowing. It is certain that it is not impotent, it must be then All-Powerful; it is not poor, it must be All-Possessing; it is not non-existent, it must be Ever-Living. The purpose is to show that these attributes and perfections that we recount for that Universal Reality are only in order to deny imperfections, rather than to assert the perfections that the human mind can conceive. Thus we say His attributes are unknowable. 
(‘Abdu’l-Baha, ’Tablet to August Forel’)