Incarnation is a religious concept whereby a god or other divine being takes on human form.
In Christianity, the Incarnation refers to the Word of God becoming man in the person of Jesus Christ. Some believers describe this as "fully God, fully man"; see Trinity. The Christian Incarnation is generally opposed by Unitarians.
The logic of the Christian Incarnation
As the Creator, God is the primary category of being. So, God can become a creature like a door can become luminous red. Our separation from God as sinners means that our efforts at salvation, or eternal life, is like groping back and forth along a very wide brick wall in total darkness, searching for an all-but-imperceptible door that leads through the wall to the other side. Many people have decided that there is no door. When the door became luminous red, we could see it, and so are able to get through the wall—if we accept that it is the only way through to the other side, and if we accept that it is unlocked and already open, and go through it. Some absolutely reject this door and refuse to go through. Some retreat back through the door in order to make their own door, and discover that they cannot break through the wall and cannot get through without using the luminous red door. One day it will be shut, and then no one remaining on the outside will be able to open it.
- Geese in the snowstorm - children's story illustrating the motivation behind the concept of Incarnation