"...whoso hath failed to acknowledge the truth of the Qur’án hath in reality failed to acknowledge the truth of the preceding Scriptures."

"It is incumbent upon us not to depart from God’s irresistible injunction and fixed decree, as revealed in the above-mentioned verse. We should acknowledge the holy and wondrous Scriptures, for failing to do this we have failed to acknowledge the truth of this blessed verse. For it is evident that whoso hath failed to acknowledge the truth of the Qur’án hath in reality failed to acknowledge the truth of the preceding Scriptures. This is but the manifest implication of the verse. Were We to expound its inner meanings and unfold its hidden mysteries, eternity would never suffice to exhaust their import, nor would the universe be capable of hearing them! God verily testifieth to the truth of Our saying!

In another passage He likewise saith: “And if ye be in doubt as to that which We have sent down to Our Servant, then produce a Súrah like it, and summon your witnesses, beside God, if ye are men of truth.” 3 Behold, how lofty is the station, and how consummate the virtue, of these verses which He hath declared to be His surest testimony, His infallible proof, the evidence of His all-subduing power, and a revelation of the potency of His will. He, the divine King, hath proclaimed the undisputed supremacy of the verses of His Book over all things that testify to His truth. For compared with all other proofs and tokens, the divinely-revealed verses shine as the sun, whilst all others are as stars. To the peoples of the world they are the abiding testimony, the incontrovertible proof, the shining light of the ideal King. Their excellence is unrivalled, their virtue nothing can surpass. They are the treasury of the divine pearls and the depository of the divine mysteries. They constitute the indissoluble Bond, the firm Cord, the Urvatu’l-Vuthqá 4, the inextinguishable Light. Through them floweth the river of divine knowledge, and gloweth the fire of His ancient and consummate wisdom. This is the fire which, in one and the same moment, kindleth the flame of love in the breasts of the faithful, and induceth the chill of heedlessness in the heart of the enemy."

-Bahá'u'lláh, The Kitáb-i-Íqán, pp. 204-205

3. Qur’án 2:23
4. "Urvatu'l-Vuthqá" is a Qur'anic term indicating the belief in the oneness of God (Fadil Mazandarani in his encyclopedic work, Asráru'l-Athár Vol.IV Pp 333-334). In the English translation of Kitáb-i-Aqdas, #117 it is translated as "Sure Handle".