If God is invisible, how is it that some authors of the Bible say that they saw him? Even though God is a spirit being and is not confined to a body, there are times when God revealed himself by taking on a form that could be seen. One example of that is something Abraham experienced. Genesis 18:1 says this: “And the LORD appeared to him by the oaks of Mamre, as he sat at the door of his tent in the heat of the day.” God took on some sort of a visible form that Abraham was able to see and have a conversation with. Of course, God was seen clearly in the person of Jesus. The incarnation involved Jesus taking on a human body.