Consider the sun. How feeble its rays the moment it appeareth above the horizon. How gradually its warmth and potency increase as it approacheth its zenith, enabling meanwhile all created things to adapt themselves to the growing intensity of its light. How steadily it declineth until it reacheth its setting point. Were it, all of a sudden, to manifest the energies latent within it, it would, no doubt, cause injury to all created things.... In like manner, if the Sun of Truth were suddenly to reveal, at the earliest stages of its manifestation, the full measure of the potencies which the providence of the Almighty hath bestowed upon it, the earth of human understanding would waste away and be consumed; for men’s hearts would neither sustain the intensity of its revelation, nor be able to mirror forth the radiance of its light. Dismayed and overpowered, they would cease to exist.
(Bahá’u’lláh, Gleanings from the Writings of Bahá’u’lláh, p. 87)