"Hath not Muḥammad, Himself, declared: “I am all the Prophets?” "

"Notwithstanding the obviousness of this theme, in the eyes of those that have quaffed the wine of knowledge and certitude, yet how many are those who, through failure to understand its meaning, have allowed the term “Seal of the Prophets” to obscure their understanding, and deprive them of the grace of all His manifold bounties! Hath not Muḥammad, Himself, declared: “I am all the Prophets?” Hath He not said as We have already mentioned: “I am Adam, Noah, Moses, and Jesus?” Why should Muḥammad, that immortal Beauty, Who hath said: “I am the first Adam” be incapable of saying also: “I am the last Adam”? For even as He regarded Himself to be the “First of the Prophets”—that is Adam—in like manner, the “Seal of the Prophets” is also applicable unto that Divine Beauty. It is admittedly obvious that being the “First of the Prophets,” He likewise is their “Seal.”

The mystery of this theme hath, in this Dispensation, been a sore test unto all mankind. Behold, how many are those who, clinging unto these words, have disbelieved Him Who is their true Revealer. What, We ask, could this people presume the terms “first” and “last”—when referring to God—glorified be His Name!—to mean? If they maintain that these terms bear reference to this material universe, how could it be possible, when the visible order of things is still manifestly existing? Nay, in this instance, by “first” is meant no other than the “last” and by “last” no other than the “first.”"

-Bahá'u'lláh, The Kitáb-i-Íqán, pp. 161-163