The test is that of sincerity:

No man shall attain the shores of the ocean of true understanding except he be detached from all that is in heaven and on earth…. 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, … inasmuch as man can never hope to attain unto the knowledge of the All-Glorious … 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…. 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….

Only when the lamp of search, of earnest striving, of longing desire, of passionate devotion, of fervid love, of rapture, and ecstasy, is kindled within the seeker’s heart, and the breeze of His loving-kindness is wafted upon his soul, will the darkness of error be dispelled, the mists of doubts and misgivings be dissipated, and the lights of knowledge and certitude envelop his being…. Then will the manifold favors and outpouring grace of the holy and everlasting Spirit confer such new life upon the seeker that he will find himself endowed with a new eye, a new ear, a new heart, and a new mind…. Gazing with the eye of God, he will perceive within every atom a door that leadeth him to the stations of absolute certitude. He will discover in all things the … evidences of an everlasting Manifestation.

When the channel of the human soul is cleansed of all worldly and impeding attachments, it will unfailingly perceive the breath of the Beloved across immeasurable distances, and will, led by its perfume, attain and enter the City of Certitude….    Bahá’u’lláh