Manifestations of God
God's Messengers to Humanity have been called The Word of God, Prophets, and Manifestations.
The key cause of religious disunity is that people believe a particular Manifestation is "better" or "more God-like" or "stronger" or "more loving" or "________".
If we look closely at what these Manifestations have told us, we'll see Their Absolute Unity of Purpose:
"He Who is everlastingly hidden from the eyes of men can never be known except through His Manifestation, and His Manifestation can adduce no greater proof of the truth of His Mission than the proof of His own Person."
Bahá’u’lláh: Gleanings from the Writings of Bahá’u’lláh, Selection XX, p. 49
"Beware, O believers in the Unity of God, lest ye be tempted to make any distinction between any of the Manifestations of His Cause, or to discriminate against the signs that have accompanied and proclaimed their Revelation. This indeed is the true meaning of Divine Unity, if ye be of them that apprehend and believe this truth.
"Be ye assured, moreover, that the works and acts of each and every one of these Manifestations of God, nay whatever pertaineth unto them, and whatsoever they may manifest in the future, are all ordained by God, and are a reflection of His Will and Purpose.
"Whoso maketh the slightest possible difference between their persons, their words, their messages, their acts and manners, hath indeed disbelieved in God, hath repudiated His signs, and betrayed the Cause of His Messengers."
"Be ye assured, moreover, that the works and acts of each and every one of these Manifestations of God, nay whatever pertaineth unto them, and whatsoever they may manifest in the future, are all ordained by God, and are a reflection of His Will and Purpose.
"Whoso maketh the slightest possible difference between their persons, their words, their messages, their acts and manners, hath indeed disbelieved in God, hath repudiated His signs, and betrayed the Cause of His Messengers."
Bahá’u’lláh: Gleanings from the Writings of Bahá’u’lláh, Selection XXIV, pp. 59-60