A mirror does not produce light by itself, but it can reflect light into dark places where the light cannot by itself reach.
When I was young, I found a small, roundish mirror, while walking along the side of a country road near my home. At some point, I made a game out of trying to reflect sunlight into the most esoteric or unlikely places I could find.
It turns out that there were a remarkably small number of places I couldn't reach with that one mirror, and even those could usually be lit up if I used a special, emergency auxiliary back-up in my other hand. A larger mirror wouldn't help - in fact, it sometimes makes it harder to reach spots that are tucked back into crevices and such. It always took an extra reflector instead.
Now, I am the mirror.
I am NOT the Light, but I can try to reflect the Light into the most esoteric and unlikely places. When I find a place I cannot reach on my own, I use my fellow reflectors in my church to help me reach it.
Being a large mirror doesn't translate to being a better mirror. It's small mirrors that make the difference - we small mirrors that will spread the Light throughout the communities we live in, working together to reach those people who have lived dark lives for too long to remember what Light really is.
You may ask, But what if my mirror doesn't reflect well? I ask in reply, how well do you know your Scripture? The better you know the Gospel, the better you can reflect the Light.
Polish your mirror.
Then go reflect the Light.