"No man shall attain the shores of the ocean of true under-standing except he be detached from all that is in heaven and on earth. Sanctify your souls, O ye peoples of the world, that haply ye may attain that station which God hath destined for you and enter thus the tabernacle which, according to the dispensations of Providence, hath been raised in the firmament of the Bayan.
THE essence of these words is this: they that tread the path of faith, they that thirst for the wine of certitude, must cleanse themselves of all that is earthly -- their ears from idle talk, their minds from vain imaginings, their hearts from worldly affections, their eyes from that which perisheth. They should put their trust in God, and, holding fast unto Him, follow in His way. Then will they be made worthy of the effulgent glories of the sun of divine knowledge and understanding, and become the recipients of a grace that is infinite and unseen, inasmuch as man can never hope to attain unto the knowledge of the All-Glorious, can never quaff from the stream of divine knowledge and wisdom, can never enter the abode of immortality, nor partake of the cup of divine nearness and favour, unless and until he ceases to regard the words and deeds of mortal men as a standard for the true understanding and recognition of God and His Prophets.
Consider the past. How many, both high and low, have, at all times, yearningly awaited the advent of the Manifestations of God in the sanctified persons of His chosen Ones. How often have they expected His coming, how frequently have they prayed that the breeze of divine mercy might blow, and the promised Beauty step forth from behind the veil of concealment, and be made manifest to all the world. And whensoever the portals of grace did open, and the clouds of divine bounty did rain upon mankind, and the light of the Unseen did shine above the horizon of celestial might, they all denied Him, and turned away from His face -- the face of God Himself. Refer ye, to verify this truth, to that which hath been recorded in every sacred Book."
-- Bahá'u'lláh, The Kitab-i-Iqan (The Book of Certitude), p. 3