A lightbulb is not luminescent, neither is a campfire nor bonfire because they use heat to generate their light. However, there are very beautiful parts of life that are of luminescent light. A firefly is luminescent (lightening bug for my Ohio friends), a rainbow is luminescent, the glow of a mother with child is luminescent, and most of the light around us is luminescent. I add that spiritual light is luminescent.
Boxers, UFC fighters, WWE wrestlers, and other sports promotions use a lot of heat to generate their light. History reveals Muhammad Ali as being someone using a lot of heat in all of his public promotions. Definitely not the same light as a rainbow, glowing mother, nor a lightening bug. The spiritual fruit is luminescent light because of the calm, tranquility, and glow without the fanfare. There are no parades nor beating of drums in the illumination of the fruit of the spirit. Think how wonderful joy, love, kindness, peace, and patience are within a light not generated with heat.
Christ is that luminescent light of the world that comes in a gentle and non-glaring glow. Reverence for Christ in us allows the spiritual fruit to illuminate our spirit. That light is all around us and we can so easily live in the light.