Jesus said to his followers 'you are the light of the world' (Matt 5.14). Note he didn't say, 'should be', 'were to be', 'better be', 'could be' but are . Christians are now the light of the world (Phil 2.15) because they are in Christ who is The Light of the world (Jn 8.12). The Christ who is within all Christians by the Holy Spirit's presence ensures that Christians everywhere shine as light in the world.
we look not to the things that are seen but to the things that are unseen --Paul, Apostle to the Gentiles