The Báb declared His mission to the haughty Mirza Muhit-i-Kirmani, one of the most outstanding exponents of the Shaykhi school

On the last day of His pilgrimage to Mecca, the Báb met Mírzá Muhít-i-Kirmání. He stood facing the Black Stone, when the Báb approached him and, taking his hand in His, addressed him in these words: “O Muhit! You regard yourself as one of the most outstanding figures of the shaykhí community and a distinguished exponent of its teachings. In your heart you even claim to be one of the direct successors and rightful inheritors of those twin great Lights, those Stars that have heralded the morn of Divine guidance. Behold, we are both now standing within this most sacred shrine. Within its hallowed precincts, He whose Spirit dwells in this place can cause Truth immediately to be known and distinguished from falsehood, and righteousness from error. Verily I declare, none besides Me in this day, whether in the East or in the West, can claim to be the Gate that leads men to the knowledge of God. My proof is none other than that proof whereby the truth of the Prophet Muhammad was established. Ask Me whatsoever you please; now, at this very moment, I pledge Myself to reveal such verses as can demonstrate the truth of My mission. You must choose either to submit yourself unreservedly to My Cause or to repudiate it entirely. You have no other alternative. If you choose to reject My message, I will not let go your hand until you pledge your word to declare publicly your repudiation of the Truth which I have proclaimed. Thus shall He who speaks the Truth be made known, and he that speaks falsely shall be condemned to eternal misery and shame. Then shall the way of Truth be revealed and made manifest to all men.” 

(Chapter 7, ‘The Dawn-Breakers’)