Channeling is where a human enters into an 'altered state of consciousness' which allows the person to become a conduit or 'channel' for the spirit of another, who can then use the channel to speak and take limited actions. This is, in essence, what a medium does to communicate with the dead. The channeling popular in some New Age circles is more extensive than the traditional medium, and sometimes involves the identity of the channeled being taking full control of the channel for a short period of time.
Jesus is one of the most reported occupants of the channelers; another popular one is Nostradamus. But most often, the speaker claims to be some little-known or unknown figure from the distant past like J.Z. Knight's prehistoric warrior Ramtha, or Boopsie's 'visitor' in the Doonesbury comic strip. Channelers typically spout generalized wisdom sayings, and/or make big claims about themselves or their listeners (like the kiss-ups channeled by Kevin Ryerson).
One of the strange things about doing a web site like Spirithome.com is that hardly a month goes by without my receiving some sort of mail package or large e-mail file from a channeler of Jesus or some apostle or saint. They come from all over the world, including nations with very few Christians such as Turkey, Uzbekistan, or Morocco. Without exception, the material is confusing, disjointed, bizarre, and contradictory. The channeler web sites I've run into on line are almost as hard to read, except for one easy-to-read site whose author I've met, and who I know to be a very good fiction writer who has much trouble dealing with reality. Channeling often leaves the mind messed up -- twisted up is more like it -- and it's as if they can no longer feel the torsion.
Let's put aside for a moment the many channelers out there who are well aware they're lying to us. It's entirely possible for someone to really open themselves up to other spirits. But us material folks don't have any real control over what spirit goes into us. We have little ability of our own to figure out spiritual beings. This lack is just part of our being material. Lying spirits abound. And once the lying spirit is in there, it can do serious damage to your soul. Your body and your brain are yours, but then some stranger comes in and starts playing around inside of them. It doesn't take long for it to settle in, rearrange the furniture, put up new walls, hang up family photos, and bring in some friends. That changes not just the arrangements, it changes your identity. Your body is part of who you are, but the visiting spirit may never have really had a material body and thus would have no idea of what it is like to be bodied. They never died because they never lived. (They won't tell you any of that, though.) There isn't enough room in there for the two of you at once. When that happens, channeling becomes much like being possessed by a demon. Even after the channeling is over, you're just not the same.
Your body is made to be a home for your spirit. Your spirit was made to work inside your body; your soul is made to be your identity. (In fact, this is what the term 'yours ' means - this is what makes you who you are.) You are a person not a pipeline. Other spirits has no business being in control even for a short while. God understands this. The Holy Spirit works through leading you into willful cooperation -- that is, working with you in your choices as you use your view, your voice and your experiences. That makes a world of difference.