To walk in the light is to walk in the light of God’s Word. If we’re not walking in the light, there’s no fellowship because light is inconsistent with darkness.
The Word reveals, for example, that as new creations, we have justification. You’re to walk in the light of your justification. You’ve been made the righteousness of God in Christ Jesus (2 Corinthians 5:21). You’re to walk in the light of your righteousness. To walk in the light of your righteousness means that you’re walking with what God thinks; His light about righteousness.
God’s light about righteousness is that, it’s a gift of God that’s imparted into anyone who believes in Jesus Christ. So, you can say, “Heavenly Father, I dwell in your light; righteousness is a gift that’s given to everyone who believes in Jesus Christ; therefore, I have that gift in the Name of Jesus. I am righteous!” That’s called walking in His light.
The carnal man however walks by his senses. He says, “I just don’t feel like God is with me today; my prayers aren’t even going through my ceiling. Oh Father, hear my prayers. I’m struggling.” You see, this man contradicts the Word of God by declaring himself a struggler, not conscious that the Bible says those who have entered into God’s rest have ceased from their struggles (Hebrews 4:10). This type of people interprets their life through their own senses. But God‘s Word does not depend on your senses.
Being born again means, you’re not of the flesh; “…they that that are in in the flesh cannot please God” (Romans 8:8). You’re to walk by the Spirit, not by your feelings. Romans 8:13 says “For “For if ye live after the flesh, ye shall die: die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.” This isn’t talking about our physical death; it’s talking about spiritual death. That means you will be cut off from God; you’ll find yourself struggling inside. But if you walk in God’s light, in His Word, you’ll live, rule and reign as a king.