When the Apostle Paul says in Galatians 5:1 For freedom Christ has set us free; stand firm therefore, and do not submit again to a yoke of slavery, he is primarily referring to being set free from a dominant Jewish framework regarding the "works of the law." The issue set before him was the hardship of living by an external written standard, and Paul wants the Gentile believers to live their lives on a more simple, yet more encompassing law - the law of love. As Jesus says in Matthew 22:
37 And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind. 38 This is the great and first commandment. 39 And a second is like it: You shall love your neighbor as yourself. 40 On these two commandments depend all the Law and the Prophets.”
The slavery of sin devalues people. The freedom of love demonstrates people's true worth. So Jesus sets us free from the power of sin, so that we would have the power to love.
What's fascinating about light is that it is one of the most used descriptions of God Himself. Psalm 104 opens this way:
Bless the LORD, O my soul!
O LORD my God, you are very great!
You are clothed with splendor and majesty,
covering yourself with light as with a garment,
Yet consider what Jesus says about us in Matthew 5:14:
“You are the light of the world.
God's light becomes our light, and so or very presence chases the darkness away.
Of course much more can be said about freedom and light, but it seems to me that it is always helpful to consider not only what Jesus has saved us from, but also what He has saved us to.
Blessings upon blessings,