The Old Testament law distinguished between unintentional and intentional sins due to their corresponding consequences. But all sin, intentional or unintentional, separates us from God and comes with consequences. Even careless sins required atonement, showing the seriousness of all sin and our need for forgiveness. In the New Testament, no such separation is made—all sin is explained as separating us from God. The good news is that Jesus’ once-for-all sacrifice provides complete forgiveness for all who trust in Him. When we who have trusted in Jesus for salvation repent of both intentional and unintentional sin, we experience His cleansing grace, are restored in fellowship with Him, and are strengthened by the Spirit to walk in greater obedience.
Those who belong to Jesus are forgiven of all their sins. They are also transformed and made new, but that transformation is a lifelong process (Philippians 1:6; 2:12–13). We will still struggle against sin, and Jesus is still faithful to cleanse us (1 John 1:9). Paul describes this constant battle between the Spirit and the flesh: "For I delight in the law of God, in my inner being, but I see in my members another law waging war against the law of my mind and making me captive to the law of sin that dwells in my members" (Romans 7:22–23). Since we are no longer judged by the Law, there is no condemnation for those who are in Christ (Romans 8:1). However, this is not an excuse to sin. Those who are truly born again do not want to walk in sin because it separates us from God: "How can we who died to sin still live in it?" (Romans 6:2).
As Christians, we have the choice to sin or not to sin, so choose life. We have changed hearts and the Spirit of God living within us, so "Let not sin therefore reign in your mortal body, to make you obey its passions. Do not present your members to sin as instruments for unrighteousness, but present yourselves to God as those who have been brought from death to life, and your members to God as instruments for righteousness. For sin will have no dominion over you, since you are not under the law but under grace" (Romans 6:12–14).
Even though the Old Testament distinguished between unintentional and defiant sins, in Christ we see that all sin—whether deliberate or careless—requires forgiveness through His sacrifice. We must take all our sins seriously, even those we may commit without realizing it, and regularly come before God in repentance. We can ask the Holy Spirit to reveal blind spots in our hearts, confess what He brings to light, and trust that Jesus’ once-for-all sacrifice fully covers us. At the same time, we are called to walk in the Spirit, choosing obedience over carelessness so sin does not gain a foothold in our lives. By living this way we can grow in holiness while resting in God’s complete forgiveness.