All that is, He contains within Himself like thoughts: the world, Himself, the All. Therefore, unless you make yourself equal to God, you cannot understand God; for like is not intelligible save to the like. Make yourself grow to a greatness beyond measure; by a leap [of intellect], free yourself from the body; raise yourself above all time, become Eternity; then you will understand God.
Believe that nothing is impossible for you; think yourself immortal and capable of understanding all, all arts, all sciences, the nature of every living being. Mount higher than the highest height; descend lower than the lowest depth. Draw into yourself all sensations of everything created, fire and water, the dry and the moist, imagining that you are everywhere, on earth, in the sea, in the sky; that you are not yet born, in the maternal womb, adolescent, old, dead, beyond death. If you embrace in your thought all things at once-all times, places, substances, qualities, quantities-you may understand God.
(The Corpus Hermetica)