In the book of Proverbs there are two verses that mention light:
“The mitzvah is a flame and the Torah, light” (Proverbs 6:23), and “The soul of man is the lamp of God” (Ibid., 20:27).
The Torah reflects the infinite light, whereas the mitzvah sheds light on a specific individual in a specific situation.
But the mitzvah is also a flame – namely, a small fire connected to the consuming fire of God.
Light enables us to see, while fire acts upon things and transforms them.
The mitzvah does both things: it changes the world by illuminating it.
–Rabbi Adin Steinsaltz