“In truth, they who plighted fealty unto thee, really plighted that fealty unto God.”

"Were any of the all-embracing Manifestations of God to declare: “I am God!” He verily speaketh the truth, and no doubt attacheth thereto. For it hath been repeatedly demonstrated that through their Revelation, their attributes and names, the Revelation of God, His name and His attributes, are made manifest in the world. Thus, He hath revealed: “Those shafts were God’s, not Thine!” 18 And also He saith: “In truth, they who plighted fealty unto thee, really plighted that fealty unto God.” 19 And were any of them to voice the utterance: “I am the Messenger of God,” He also speaketh the truth, the indubitable truth. Even as He saith: “Muḥammad is not the father of any man among you, but He is the Messenger of God.” 20 Viewed in this light, they are all but Messengers of that ideal King, that unchangeable Essence. And were they all to proclaim: “I am the Seal of the Prophets,” they verily utter but the truth, beyond the faintest shadow of doubt. For they are all but one person, one soul, one spirit, one being, one revelation. They are all the manifestation of the “Beginning” and the “End,” the “First” and the “Last,” the “Seen” and “Hidden”—all of which pertain to Him Who is the innermost Spirit of Spirits and eternal Essence of Essences. And were they to say: “We are the servants of God,” this also is a manifest and indisputable fact."  ...

-Bahá'u'lláh, The Kitáb-i-Íqán ,pp. 178-179

 18. Qur’án 8:17. 
 19. Qur’án 48:10. 
 20. Qur’án 33:40.