Westminster Project 6.5 - 6

5. This corruption of nature remains in those who are regenerated during this life. Although it is pardoned and mortified through Christ, yet this nature itself and all the actions coming from it are truly and properly sin. 

6. Every sin, both original and actual, being a transgression of the righteous law of God and contrary to it, by its nature brings guilt on the sinner, by which the sinner is bound over to the wrath of God and the curse of the law, and so made subject to death, with all manner of spiritual, temporal, and eternal miseries. 
(WCF 6.5-6)

In the book of Romans, the Apostle Paul pulls back the curtain to reveal a profound inner struggle between his ‘flesh’ and ‘spirit.’ He writes,
“For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. For I do not do the good I want, but the evil I do not want is what I keep on doing. Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me.”
— Romans 7:18-20 (ESV)

Simply put, Paul’s observation aligns with what our confession teaches: though we are saved by grace through faith, the corruption of our sinful nature remains in us throughout this life.

As we have seen in our confession over these weeks, our first father, Adam, was the root of all humanity. Because the root was corrupted by sin, the entire human family has been tainted (WCF 6.3). So, even though sin is pardoned and mortified through Christ, the stark reality for every Christian is this: although Jesus Christ has won the war for your soul and eternity, you are now engaged in a lifelong battle between your ‘flesh’ and your ‘spirit.’ This battle involves rejecting what was once natural to you—the sin you once loved—and taking up your cross to follow Jesus on the narrow path (Matt 7:13-14; 16:24-26).

Here is the wonderful news: none of us fight this battle alone. God is personally engaged and invested in His people because He has purchased us with the precious blood of His Son and filled us with His Holy Spirit. What He has begun in us, He will bring to completion (Rom 3:21-25; Eph 1:13-14; Phil 1:6). That is why the born-again child of God struggles, strives, and seeks to mortify sin. This sinful nature and all its actions are truly sin and deeply offensive to our enlightened and tender conscience (Eph 1:18; 1 Tim 1:19). Every Christian wrestles with their own desires, but through the power of the Spirit, we seek to kill the sin that entangles us because Jesus is now our Master, and we desire to please Him, not grieve His Spirit (Rom 8:13; Heb 12:1-3; cf. Eph 4:30).

So, if you are struggling with sin, take heart, dear one. God is at work in you and will never leave or forsake you in the fight. Keep fighting because every sin—both original (inherited) and actual (committed)—is a transgression of God’s righteous law. Sin brings guilt and binds the sinner over to God’s wrath and the curse of the law, from which we have been graciously delivered (Jude 1:23).
No true child of God desires to be like a pig wallowing in the mire, but Scripture warns that we are in danger of becoming like dogs returning to their vomit, with the condition from which we were delivered becoming worse (2 Pet 2:22; Matt 12:43-45). Therefore, resist sin in the power and knowledge of the gospel. When we quench the Spirit and reject God’s Word, we subject ourselves to death—with all its spiritual, temporal, and eternal consequences.