Manifestations of God, according to Bahá'í teachings, are more than Messengers of God. They are "universal Prophets", and are distinguished from minor prophets such and Isaiah and Jeremiah in that they are founders of new religions:
Universally, the Prophets are of two kinds. One are the independent Prophets who are followed; the other kind are not independent, and are themselves followers.
The independent Prophets are the lawgivers and the founders of a new cycle.... Without an intermediary They receive bounty from the Reality of the Divinity, and Their illumination is an essential illumination. They are like the sun which is luminous in itself.... The other Prophets are followers and promoters, for they are branches and not independent; they receive the Bounty of the independent Prophets, and they profit by the light of the Guidance of the universal Prophets. They are like the moon which is not luminous and radiant in itself, but receives its light from the sun.1
Bahá'u'lláh explains that the Manifestations are NOT God incarnate:
To every discerning and illuminated heart it is evident that God, the unknowable Essence, the divine Being, is immensely exalted beyond every human attribute, such as corporeal existence, ascent and descent, egress and regress.2
However, they are not normal human beings, either:
But the individual reality of the Manifestations of God is a holy reality, and for that reason, it is sanctified, and in that which concerns its nature and quality, is distinguished from all other things.3
An analogy commonly used to describe the nature of the Manifestations likens God to the sun. The Manifestations are like pure, spotless mirrors that reflect on Earth the attributes of God. The sun itself does not descend to Earth, but its qualities are made manifest when its rays are reflected.
Manifestations of God include Abraham, Krishna, Moses, Zoroaster, Buddha, Jesus, Muhammad, The Báb, and Bahá'u'lláh.
1. `Abdu'l-Bahá, Some Answered Questions, p. 164.
2. Bahá'u'lláh, Kitab-i-Íqán. p. 98/79.
3. `Abdu'l-Bahá, Some Answered Questions, p. 154.