Answer: To “walk in the light” is a common metaphor within Christian culture. It is often taken to mean “acting correctly” or even “living openly.” Biblically, however, the phrase has the idea of relinquishing sin by following Jesus.
The only Old Testament occurrence of this precise phrase is in Isaiah 2:5, “O house of Jacob, come and let us walk in the light of the Lord.” The Psalms contain similar phrases (56:13; 89:15), as does Isaiah (9:2; 50:10-11; 59:9).
In the New Testament, “walking in the light” is directly related to following Jesus, who said, “I am the light of the world. He who follows me shall not walk in darkness, but have the light of life” (John 8:12). While this verse does not directly say, “Walk in the light, i.e., Jesus,” it does pointedly warn of doing the opposite; therefore, those who follow Jesus are “walking in the light.”
To “walk” is, in short, to live one’s life. One’s lifestyle or way of life can be considered a “walk.” The word also indicates progress. Walking is related to growth; it is taking steps toward maturity. “Light” in the Bible can be a metaphor for life, happiness, righteousness, or understanding. The Bible is clear that light comes from the Lord God, the “Father of the heavenly lights” (James 1:17). He is the opposite of evil. Putting it all together, “walking in the light” means “growing in holiness and maturing in the faith as we follow Jesus.”