"The body of my spirit"

In the Book of Mormon there is a story where Jesus appears to a man known simply as the 'Brother of Jared.' The story happened thousands of years before Jesus was born but the brother of Jared saw Jesus in the form of a man. He thought that Jesus had "flesh and blood." Jesus corrected him saying, "Behold, this body, which ye now behold, is the body of my spirit; and man have I created after the body of my spirit; and even as I appear unto thee to be in the spirit will I appear unto my people in the flesh." Ether 3:16

What does it mean? Body of my Spirit? Aren't spirits supposed to be ephemeral things like mist or something? What are your thoughts?