Not long after Baha’u’llah’s arrival in Kurdistán, Shaykh Sultán [The father-in-law of Áqáy-i-Kalím, Bahá’u’lláh’s brother] has related, He was able, through His personal contacts with Shaykh ‘Uthmán, Shaykh ‘Abdu’r-Rahmán, and Shaykh Ismá‘íl, the honored and undisputed leaders of the Naqshbandíyyih, the Qádiríyyih and the Khálidíyyih Orders respectively, to win their hearts completely and establish His ascendancy over them. The first of these, Shaykh ‘Uthmán, included no less a person than the Sulṭán himself and his entourage among his adherents. The second, in reply to whose query the “Four Valleys” was later revealed, commanded the unwavering allegiance of at least a hundred thousand devout followers, while the third was held in such veneration by his supporters that they regarded him as co-equal with Khálid himself, the founder of the Order.
- Shoghi Effendi (‘God Passes By’, chapter 7)