"God, the Creator, saith: There is no distinction whatsoever among the Bearers of My Message. They all have but one purpose; their secret is the same secret. To prefer one in honor to another, to exalt certain ones above the rest, is in no wise to be permitted."

"The songs which the bird of thine heart had uttered in its great love for its friends have reached their ears, and moved Me to answer thy questions, and reveal to thee such secrets as I am allowed to unfold. In thine esteemed letter thou hadst inquired which of the Prophets of God should be regarded as superior to others. Know thou assuredly that the essence of all the Prophets of God is one and the same. Their unity is absolute. God, the Creator, saith: There is no distinction whatsoever among the Bearers of My Message. They all have but one purpose; their secret is the same secret. To prefer one in honor to another, to exalt certain ones above the rest, is in no wise to be permitted. Every true Prophet hath regarded His Message as fundamentally the same as the Revelation of every other Prophet gone before Him. If any man, therefore, should fail to comprehend this truth, and should consequently indulge in vain and unseemly language, no one whose sight is keen and whose understanding is enlightened would ever allow such idle talk to cause him to waver in his belief.

The measure of the revelation o
f the Prophets of God in this world, however, must differ. Each and every one of them hath been the Bearer of a distinct Message, and hath been commissioned to reveal Himself through specific acts. It is for this reason that they appear to vary in their greatness. Their Revelation may be likened unto the light of the moon that sheddeth its radiance upon the earth. Though every time it appeareth, it revealeth a fresh measure of its brightness, yet its inherent splendor can never diminish, nor can its light suffer extinction."

-Bahá'u'lláh, Gleanings From the Writings of Bahá’u’lláh, pp. 78-79