Light is the only pure source that has unlimited energy. It keeps on shining no matter the environment.

So do you get the message?
I'm saying that be the light to the world. Means to be a True-Believing-Christian to the world.
Do not turn it off where you are not with Christians and do whatever is dark.
Dark = sin.

You have to be that/the light to the world. Because we know the Truth. That Truth is that Jesus is God, and He die for us on the cross to die for our sins and rose on the third day as a message He conquer Death. For that purpose, we are save and if we believe in Jesus as God. We have Salvation in Christ.

So be the influence, be the role-model, stand for what is right, in Jesus Christ.
Be that light that others may see the Truth/light and let them know the Truth.

So be the light to the world
Who is the world. People that haven't heard about Jesus Christ like your friends, family, strangers and etc.

These people need us because they live in the dark and have not seen the light. And you are the light because you know and believe in the Truth.

Let it shine for Jesus Christ.

Be the light.

God loves you