If you are devoted to a particular religion, you are devout, not devote. You may be a devout Christian, a devout Catholic, a devout Jew, a devout Buddhist, etc.
“Devote” (with no final D) is a verb, something you do rather than something you are. You may devote a lot of your time to working at a food bank, or building model airplanes, for instance.
If you are enthusiastically dedicated to an activity, a cause or person, you are devoted to it. You can be devoted to your gardening, to collecting money for Unicef, or to your pet. You can be a devoted father, husband, or a devoted runner or knitter. You can be a devoted fan of the Seattle Storm. If you have a lot of fans, you may have a devoted following. The devotion involved need not be religious.