When Jesus spoke again to the people, he said, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life.” John 8:12
Following Jesus is the condition of two promises:
First, His followers will never walk in darkness, which is a reference to the assurance of salvation we enjoy. As true followers of the Light, we will never follow the ways of sin, never live in a state of continually sinning (1 John 1:5–7). Rather, we repent of our sin in order to stay close to the Light of the world.
The second promise is that we will reflect the Light of Life. Just as He came as the Light of the world, He commands us to be “lights,” too. In Matthew 5:14–16 we see believers depicted as the light of the world. Just as the moon has no light of its own, reflecting the light of the sun, so are believers to reflect the Light of Christ so that all can see it in us. The Light is evident to others by the good deeds we do in faith and through the power of the Holy Spirit.
The emphasis here is maintaining a credible and obvious witness in the world, a light-style that shows us to be faithful, God-honoring, trustworthy, sincere, earnest, and honest in all that we do. Also, we should always be ready to give an account of the hope that we have (1 Peter 3:15), for the gospel Light we have is not to be covered, but made obvious for all to see and benefit from, that they, too, may leave the darkness and come into the Light.