The conclusion of a three-part devotional from 1 John 1:

Verse 5 “Now this is the message we have heard from Him and declare to you: God is light, and there is absolutely no darkness in Him.”
The first part we need to know, is that God is perfect and holy. He has no sin (darkness) in Him. By contrast, we live in darkness and sin. This is what separates us from God and prevents us from having fellowship with Him.
Light and darkness cannot coexist. If it is light, it is not dark. If it is dark, it is not light. So we, in our darkness, cannot have fellowship with God, who is light.
This also prevents us from being able to go to heaven when we die.
That is our problem, and we have a choice to make. One option we have is to try to solve the problem of our sin by ourselves, but that doesn’t work, because:
Verse 6 “If we say, ‘We have fellowship with Him,’ and walk in darkness, we are lying and are not practicing the truth.”
Many people say, “I am a Christian. I was born a Christian. I am very religious. I go to church. I do good things more often than I do bad things. I’m just not bad enough to deserve hell. Hell is for pagans, and I am a Christian.” But they have never come to Jesus personally to trust in Him alone for salvation. They have never repented in their hearts and trusted the fact that He died in their place on the cross for their sins to get them to heaven. They have instead trusted in their own good works. So their sins have never been forgiven. The darkness has never been taken away. They still live in darkness and carry a lifetime of unforgiven sin around on their backs. They may tell others, and tell themselves, that because they are religious, they have fellowship with God. But God’s word says that if we do that, we are lying—to ourselves, to God, and to others. We are not practicing truth. The truth is, we don’t have fellowship with Him when we remain in darkness.
So that’s one option of what we can do, and we’ve seen that it can’t work. So what will work to solve our problem, and give us eternal life and a relationship with God?
Verse 7 “But if we walk in the light as He Himself is in the light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin.”
We come into the light. Jesus is the light of the world. He came and lived a perfect life, never sinning, not even once. He is so holy and perfect and righteous, that when we come by faith into His presence, we are exposed for how sinful we are. We believe that He lived a perfect life in our place, and that He died on the cross in our place and rose again. Then we find forgiveness of all our sin, and He places His light within us then. No longer do we walk in darkness, not knowing how to live properly. Now we have a relationship with Him, and the blood He shed for us on the cross takes away our sin and gives us eternal life.

Once we have by faith received eternal life in heaven, we need to live our lives walking in the light. We can continue to have a close relationship with Him, by letting Him continually cleanse us of our sin. We will sin less than we did before He saved us, but we would be lying to say we never have sin. But if we are truthful and honest with God about our sin, He has a solution that keeps our relationship with Him, even when we fail Him:
Verses 8-9 “If we say, ‘We have no sin,’ we are deceiving ourselves, and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.”

From this, we learn two things about Christ’s forgiveness of our sins. One, He is “faithful” to forgive us. That means you can trust Him to do it. He will keep His promise. If you have trusted Him as your Savior, you don’t have to worry that on Judgment Day you will come before Him and hear, “You know, I forgave you for a lot. And you kept sinning, and sometimes I felt like forgiving you, but there are these other sins that just offended Me so much that I decided not to forgive them. You’re going to have to go to hell after all.” No, Jesus will not do that to you. He is faithful to forgive us our sins. If you have come to Him and trusted Him alone as your Savior, you can rely on Him and know that you have eternal life, and that He will continue to cleanse you of all unrighteousness.
The second thing we learn is that He is “just” or “righteous” to forgive us our sins. That means simply that He is doing the right thing to forgive us when we confess, and that He is the one that has a right to do so. If you come to confess your sins to me, I have no right to forgive you and cleanse you. I am just a man. I have sinned myself. It would be not right, but blasphemous, for me to claim I can forgive your sin. If you go to a priest to confess your sins, he does not have the standing before God that allows him to cleanse you of your sins.
You must come to Jesus Himself, and confess your sinfulness to Him, and trust Him because He died in your place, to give you forgiveness of sins, eternal life, and a continual close relationship with God.