"I am the light of the world. If you follow me, you won't have to walk in darkness, because you will have the light that leads to life."
In Ephesians 5, Paul talks about the practicalities of walking in that light.
Ephesians 5
1 Imitate God, therefore, in everything you do,
because you are his dear children.
2 Live a life filled with love, following the example of Christ.
He loved us and offered himself as a sacrifice for us, a pleasing aroma to God.
3 Let there be no sexual immorality,
impurity,
or greed among you.
Such sins have no place among God's people.
4 Obscene stories,
foolish talk,
and coarse jokes;
these are not for you.
Instead, let there be thankfulness to God.
5 You can be sure that no immoral, impure, or greedy person will inherit the Kingdom of Christ and of God.
For a greedy person is an idolater, worshiping the things of this world.
6 Don't be fooled by those who try to excuse these sins,
for the anger of God will fall on all who disobey him.
7 Don't participate in the things these people do.
8 For once you were full of darkness,
but now you have light from the Lord.
So live as people of light!
9 For this light within you produces only what is good and right and true.
10 Carefully determine what pleases the Lord.
11 Take no part in the worthless deeds of evil and darkness;
instead, expose them.
12 It is shameful even to talk about the things that ungodly people do in secret.
13 But their evil intentions will be exposed when the light shines on them,
14 for the light makes everything visible.
This is why it is said,
"Awake, O sleeper,
rise up from the dead,
and Christ will give you light."