When you love someone you want the best for them. When you love someone, you also fear the worst happening and fight to protect them. So what's the worst? It isn't car wrecks or cancer.
The worst that could happen is that the sinful desires which, as Peter wrote, “wage war against our souls” (1 Peter 2.11) would win that war against our souls. The worst thing ever would be that grace would no longer sound amazing to us, that we would no longer “tremble at God’s word” (Isaiah 66.2), and that Jesus Christ would no longer look beautiful and glorious. The worst that could happen would be that we would lose our faith in Jesus Christ and be satisfied instead with the things of this world.
We have an enemy. It wants to claim our lives and destroy us. And by the way, our ultimate enemy is NOT Satan. The worst thing Satan can do to us is influence us to sin. Our worst enemy resides within us: it is our sinful desires. It is our tendency towards pride, insecurity, distrust of God, selfishness, greed, covetousness, lust, gossip, and the allurements of the world.
Our great battle, our great calling, our great goal, and our great purpose is to fight sin. As Paul insists in Romans 8.13, “…if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live.” Therefore we are mercifully commanded in Colossians 3.5 to, “Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.” This is the truth about Christians: “…those who belong to Christ Jesus have crucified the flesh with its passions and desires.” (Galatians 5.24)
The author of the book of Hebrews lovingly reminds us, “Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.” (Hebrews 3.12)
He’s warning us! He’s warning us about being content and thinking that we have our sin under control! He’s warning us that we could fall away from God unless we take care; take action, work, fight our sin! As the great theologian John Owen wrote, “We must be about the business of killing sin, or sin will be killing us.”
It is here that you might answer, “But I thought that Christians can’t lose their salvation!”
And you’re right – they can’t. Romans 8.30 insists, “And those whom [God] predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified.”
Salvation is sure for God’s people from start to finish.
We then ask, “Then why these texts warning us about losing our salvation?” That is a great question – why did God include passages of warning for His people if their salvation is sure? Here is the answer – God’s salvation is not a mathematical equation or a computer program. God’s salvation involves the changed hearts, desires, and lifestyles of real people. God’s salvation involves hearts that are changed to love Him and obey Him and fight against the sin that motivate them to do otherwise. Therein, passages of warning are mercifully included in Scripture because those whose hearts God has changed will respond to them. God’s people, the chosen and the saved, will be moved by such passages of warning to repent of their, to fight sin, and turn to the cross. Passages of warning are a gift from above. They keep us from being lazy and comfortable when we are called to fight.
So how do we fight our sin? Scripture speaks of many ways. But the author of Hebrews has something specific in mind. In verse 13 of chapter 3, immediately following his gracious warning, he writes, “But exhort one another every day, as long as it is called "today," that none of you may be hardened by the deceitfulness of sin.”
This is big. Instead of falling away from our God, we are to exhort one another on a regular basis. To exhort is to “strongly encourage or urge someone to do something.” God is telling us here that an antidote to sin is regular encouragement and urging from other Christians. We see again just how deeply we need one another. In a way, our salvation depends upon our deep involvement in one another’s lives.
Why do we need one another in the fight against sin? We saw it the answer in verse 13. The answer is that sin is deceitful. Our sin lies – it looks good, but isn’t. It looks contained, but rumbles beneath the surface. It is like quicksand; the ground looks fine but sucks you down to your death. We need others because sin is like the ketchup smeared all over your chin. You think you look good out there on the town, but the rest of us know better. We need one another because sin is deceitful. We can’t see it on our own because our sin deceives us. We need others to exhort us, and we need to rightly exhort others. As the Psalmist wrote in 141.5, “Let a righteous man strike me—it is a kindness; let him rebuke me—it is oil for my head; let my head not refuse it.”
Let's love one another and protect one another. That means fighting sin. That means exhorting others, and it means being exhorted.