There is no such verse. He had not yet claimed to be a Manifestation of God when he wrote it.
These words have streamed from the pen of this Wronged One in one of His Tablets: "The purpose of the one true God, exalted be His glory, hath been to bring forth the Mystic Gems out of the mine of man -- they Who are the Dawning-Places of His Cause and the Repositories of the pearls of His knowledge; for, God Himself, glorified be He, is the Unseen, the One concealed and hidden from the eyes of men.
(Bahá'u'lláh, Epistle to the Son of the Wolf, p. 13)
Our purpose in revealing these convincing and weighty utterances is to impress upon the seeker that he should regard all else beside God as transient, and count all things save Him, Who is the Object of all adoration, as utter nothingness.
(Bahá'u'lláh, Gleanings from the Writings of Bahá'u'lláh, p. 266)
The Purpose of the one true God, exalted be His glory, in revealing Himself unto men is to lay bare those gems that lie hidden within the mine of their true and inmost selves.
(Bahá'u'lláh, Gleanings from the Writings of Bahá'u'lláh, p. 287)
The purpose of the one true God in manifesting Himself is to summon all mankind to truthfulness and sincerity, to piety and trustworthiness, to resignation and submissiveness to the Will of God, to forbearance and kindliness, to uprightness and wisdom.
(Bahá'u'lláh, Gleanings from the Writings of Bahá'u'lláh, p. 299)
Thou well knowest, O my Lord, that in revealing myself I have sought only to reveal Thy Cause, and have turned to no one except for the sake of Thy Revelation and for the purpose of manifesting Thy loving-kindness.
(Bahá'u'lláh, Prayers and Meditations by Bahá'u'lláh, p. 65)
More to follow. . .