“He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world” (1 John 2:2). When the Bible says that Christ was the sacrifice for all sin, it does not mean that all sin was automatically forgiven. It simply means that the offering to secure forgiveness for the whole world has been made; whether that offering actually results in the forgiveness of any individual is another matter, because the offering must be accepted by faith. Our way back to God has been prepared by Christ; the question now is, we will avail ourselves of the opportunity?
Christ died for all sin; that is, His sacrifice was completely sufficient to pay for the sins of the entire world. But forgiveness only comes to an individual when he or she repents and believes (see Mark 1:15). Until we accept (by faith) the provision of God in Christ, then we are still in our sins. Those who die in unbelief die in all their sin—they are unforgiven liars, murderers, adulterers, etc. (Revelation 21:8). Those who trust in Christ for their salvation do not die in sin; they die in Christ, with all sins forgiven. We are justified by faith (Romans 5:1); without faith, we are condemned (John 3:18). Forgiveness is received through faith in Christ and comes with the promise of an eternity in heaven; lack of faith keeps us unforgiven and consigned to an eternity in hell.
In the Bible, belief, or faith, is more than just thinking something is a fact. Faith has more to do with trust and personal acceptance, deliberate acts of one’s will. So, in Scripture, the sin of unbelief is not merely ignorance; rather, it is willfully refusing God’s free gift of forgiveness of sin—including the sin of unbelief.
When God offers to forgive a man’s sin if he believes, logic dictates that his response cannot be, “No, I refuse to believe in You, but forgive my sins anyway.” Forgiveness is a conditional offer: if the required condition is met (faith), then the promised result occurs (forgiveness). Faith in Christ is how people rightly respond to God’s offer of salvation.
The Bible says much about the necessity of choosing faith in Christ and the results of unbelief. Christ longed to gather the sinful inhabitants of Jerusalem to Himself, yet they remained in their sin; Jesus’ condemnation places the onus directly on them: “You were not willing” (Luke 13:34). Their unbelief kept them away from Christ, their only salvation.
On the logic of requiring belief: “And without faith it is impossible to please God, because anyone who comes to Him must believe that He exists and that He rewards those who earnestly seek him.” (Hebrews 11:6)
On unbelief as an act of will, a deliberate choice: “Even after Jesus had performed so many signs in their presence, they still would not believe in Him.” (John 12:37)
On why there is no excuse for unbelief: “The wrath of God is being revealed from heaven against all the godlessness and wickedness of people, who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.” (Romans 1:18-20)
On the spiritual damage of unbelief: “What benefit did you reap at that time from the things you are now ashamed of? Those things result in death!” (Romans 6:21) “Rather, we have renounced secret and shameful ways;” [but] “The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel that displays the glory of Christ, who is the image of God.” (2 Corinthians 4: 2, 4)
On the justice of punishment for unbelief: “This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil.” (John 3:19)
Finally, to be sure you know what a true believer must believe in order to be a forgiven Christian, here is a summary.
The Bible is clear that the only way to get into God’s perfect heaven is to be as perfect (pure and sinless), as God Himself (Matthew 5:20, 48; Luke 18:18–22). Even if you sin only once in your whole life, you have broken all of God’s law, just as breaking one link in a chain breaks the whole chain (James 2:10). God’s perfect justice means that every sin must be punished. That penalty is death in the form of eternal separation from God in hell (Exodus 32:33).
No human can meet God’s perfect standard, so without a supernatural Savior to rescue us, we are all lost sinners (Acts 15:10; Romans 3:9–23). God loves you and wants to rescue you from hell (John 3:16; 2 Peter 3:9). So He sent his own perfect Son to take your punishment on Himself—his life for yours— paying your debt to God in full by dying on the cross, and forever freeing you from God’s righteous condemnation. Every one of your sins—past, present, and future—is forgiven if you choose to accept that gift of forgiveness by faith (believing and trusting God to keep His promise), when you repent (turn away from) your sins (Luke 24:47; Acts 11:18; 2 Corinthians 7:10) and ask Him to save you (Joel 2:32; Acts 2:21). The blood of Jesus covers your sins so that God sees you as perfect as his own Son (Isaiah 53:4–6; 2 Corinthians 5:21).
The instant you accept God’s free gift by faith, you are changed: “Therefore, if anyone is in Christ, he is a new creation: The old has gone, the new is here!” (2 Corinthians 5:17). You become God’s own beloved child (1 John 3:1), an eternal relationship that can never be broken (Romans 8:38–39; Ephesians 1:13–14). God as Father, Son and Spirit indwell you and make their “home” with you (John 14:17, 23). You can see why the Gospel of Christ is called Good News (Luke 2:10; Acts 5:42, 14:15)! In accepting this gift, you agree that you belong to God (1 Corinthians 6:19-20). You are not your own because He bought (redeemed) you with the precious blood of his Son (1 Peter 1:18–19).
This amazing free gift of eternal salvation cannot be earned by any good thing you do (John 3:16; Romans 3:21–25; Ephesians 2:8–9). In fact, trying to earn it by your own efforts, as though you could please God enough to earn his acceptance, is harshly condemned in the Bible (Galatians 1:6–9). That is the difference between Christianity and virtually all the other religions in the world, with their manmade rules about what people must or must not do in the hopeless attempt to win God’s favor and gain eternal life for their souls.
Your salvation is free, a priceless gift from God more valuable than the entire world (Matthew 13:44; 16:26). And so the author of Hebrews asks, “How shall we escape if we ignore so great a salvation?” (Hebrews 2:3). “Today, if you hear his voice, do not harden your hearts” (Hebrews 3:7–8). “I tell you, now is the time of God’s favor, now is the day of salvation” (2 Corinthians 6:2).