The easy way is to go into the attribute editor for your light and turn on light glow there, just increase the slider to the right and render
You'll figure out the other options while you are in there.
The other way is to use a lightglow utility in Hypershade and attach it to your shader. Experiment and have fun
Red bellows of flame have blackened my stones
Convulsing my frame and cracking my bones
Hell's dragons of steel who roar in their chains
Crawl into my caves to suck out my veins.....
-The Mountain P.F.M.