Light Saber Glow and Motion Blur

Make a very simple material for the core, with no self-illumination.

Make the core a separate object from the handle and link to the handle.

Animate the handle swinging around so you can test the blurring and glow at different frames/angles.

Right click/Properties on the light core and doe this:

[object channel 1 and enable object motion blur]

For the Blur

Go into the Render Dialogue/Render tab and set up the Object Motion Blur:

For the Glow

Go into the Render/Effects dialogue and set up a Lens Effect/Glow. You will definitely have to play with Size and Intensity.

Note that Use Source color is set to 100; this utilizes the simple bright map you made for the core glow color.

You objective is to get something like this as the sword makes a fast long swing: