That the Manifestations of Divine justice, the Day Springs of heavenly grace, have when they appeared amongst men always been destitute of all earthly dominion and shorn of the means of worldly ascendancy, should be attributed to this same principle of separation and distinction which animateth the Divine Purpose. Were the Eternal Essence to manifest all that is latent within Him, were He to shine in the plentitude of His glory, none would be found to question His power or repudiate His truth. Nay, all created things would be so dazzled and thunderstruck by the evidences of His light as to be reduced to utter nothingness.
How, then, can the godly be differentiated under such circumstances from the froward?

This principle hath operated in each of the previous Dispensations and been abundantly demonstrated…. It is for this reason that, in every age, when a new Manifestation hath appeared and a fresh revelation of God’s transcendent power was vouchsafed unto men, they that misbelieved in Him, deluded by the appearance of the peerless and everlasting Beauty in the garb of mortal men, have failed to recognize Him.

Gleanings From the Writings of Bahá’u’lláh, P. 72