In order for us to understand that there is absolutely and without any doubt no condemnation for those in Christ Jesus, we must first be under the conviction that there is even a need for condemnation. In other words, we will not believe that Christ has secured a condemnation-free life for his people until we come under the conviction that God is righteous and that man is unrighteous. Simply put, that God is righteous means God lives and acts in accordance with what is right or just (Rom 1:16–20; cf. 2:8, 14–15; 5:16; 7:12; 10:3). That man is unrighteous means men live and act in accordance with what is not right or unjust (Rom 3:9–10; cf. 3:23; 5:6–8, 12).
Despite this fierce schism between the mortal and Divine, God established his righteous standard for unrighteous mankind to live by, which produces lasting happiness and satisfaction. He established this in what is called the Law—a written code (Genesis–Deuteronomy) that was meant to guide every facet of his people’s life. He gave this Law to the prophet Moses in order that his people might fear God and no longer sin. But herein lies the problem: men believe happiness and satisfaction come from other things instead. That is, we believe that what God has given his people to satisfy them is really not all that satisfying. And that is unrighteous.
But how has God solved this problem of man's unrighteousness? The book of Romans is about God justifying (i.e., declaring righteous) those who are unrighteous. And Romans 8:1–4 explains how this happens and why eternal life is secured for every true believer in Jesus Christ. Before we examine how these four verses relate to one another, let us first see the text as a whole:
(1) “There is therefore now no condemnation for those who are in Christ Jesus.(2) For the law of the Spirit of life has set you free in Christ Jesus from the law of sin and death. (3) For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh, (4) in order that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit.” (Rom 8:1–4)
No Condemnation for Those in Christ Jesus (v. 1)
So, now to our first point, which is the main point.
“Therefore, there is now no condemnation for those who are in Christ Jesus” (Rom 8:1)
Since God is righteous and man is unrighteous, and since man, because of his unrighteousness, deserves condemnation (Rom 5:16), therefore, how can Paul say that there is no condemnation? To be condemned is to be rendered guilty and then punished. God’s eternal punishment is the condemnation for which Christ died to rescue people from. So, for what reason should those “in Christ” not be punished for their evident sin?
The Reason (v. 2)
Which brings us to verse 2.
“For the law of the Spirit of life has set you free in Christ Jesus from the law of sin and death” (Rom 8:2)
In other words, the reason for no condemnation is due to the Spirit’s liberation. Condemnation will never overtake those who have been liberated (i.e., freed) from the grip of sin. And the Spirit must do this; otherwise you are a dead man. So, the question before us now is: precisely what is the freedom in v. 2?
When the Holy Spirit comes, he changes your desires and passions, so that, as the chancellor of my school writes, “[Christ] is no more resistible than the enjoyment of your favorite food is resistible when it is [already] in your mouth.” God, through the power of his Spirit, frees you from the desire and passion to sin, so that the Romans 6:22 is now a reality: “But now that you have been set free from sin and have become slaves of God, the fruit you get leads to sanctification and its end, eternal life.” You formerly desired sin and now you hate sin. You once lived for yourself and your own glory; now you live for Christ and his glory. That is freedom. You are now free, by the power of the gospel, to love and obey God, whereas before you were enslaved by the passions that forced you to act for your own glory.
The Impossibility of the Law (v. 3)
I said earlier that God originally established a righteous standard for mankind to live by, from which lasting happiness and satisfaction would come. And that he established all of this in what is called the Law, which was given to the great prophet, Moses. When any person comes face-to-face with the Law of the Old Testament he stands condemned, because no human can uphold the Law. That is, no one is capable of obeying the Law and thus accepted before God by their works. If man could uphold the law by their own power, they would have something to boast about before God (Rom 4:2). This is not the case. “For by works of the law no human being will be justified in his sight, since through the law comes knowledge of sin” (Rom 3:20). Thus, the Law commands, but nobody can uphold. This impossible feat is what the Law presents people with. It’s like commanding a blind person to read. It cannot happen. And this reality is revealed in v. 3:
For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh ...
So, what we must understand about the Old Testament is that it only commanded and never enabled. That is, the OT commanded impossible tasks which you and I and any other human on the planet could not and cannot keep; and never once provided any power or strength, with which to obey. Take, for example, the command of God in Deut 10:16 to “Circumcise, therefore, the foreskin of your heart, and be no longer stubborn.” Now, it was easy to circumcise the flesh. Fathers would simply take a knife and cut the foreskin off of their infant boys. But it is a completely different command to circumcise the foreskin your own heart. How can you do that? You can’t! And that is precisely the point. You need the Holy Spirit. Rom 2:29: “ … circumcision is a matter of the heart, by the Spirit, not by [what you do with your hands].”
Therefore, God’s people in the OT needed God to do what they could not. “But to this day the LORD has not given you a heart to understand or eyes to see or ears to hear” (Deut 29:4). They couldn’t fulfill the command of the Law because the LORD hadn’t given them a heart to even obey it! Therefore, the Law condemned them for their sin and displayed for them on every page that they needed God to do that which they cannot do themselves. That is what “weakened by sinful flesh” in v. 3 means. Because of their sin, OT Israel couldn’t experience the ultimate blessings that come from fulfilling the Law. But it is not as though the Law was insufficient. No, rather, the Law was perfect.
Psalm 19:7–8: “The law of the LORD is perfect, reviving the soul; the testimony of the LORD is sure, making wise the simple; the precepts of the LORD are right, rejoicing the heart; the commandment of the LORD is pure, enlightening the eyes.”
This text says the Law is not only perfect, but it revives your soul, it makes you wise, it causes your heart to overflow with exceeding joy, and it opens your eyes to reality. Yet, it was “weakened,” in that it revealed to man his sinfulness (Rom 5:20) and utter inability to obey it, without providing the means to obey. But the Law didn’t stop there. Just as the Law promised blessing for obedience and curse for disobedience, and although we can’t keep the Law, it promised that the Lord himself would keep it for us.
In other words, ultimately, what the Law couldn’t provide, the Lord promised that he himself would provide. “And the LORD your God will circumcise your heart and the heart of your offspring, so that you will love the LORD your God with all your heart and with all your soul …” (Deut 30:6; cf. Jer 31:33; 32:39; Ezek 11:19; 26:27; 36:27).
The problem is not with the God’s Law, but with man’s heart.
So, what does all this have to do with v. 3: “By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh” (Rom 8:3)? Verse 3 explains how God achieved the impossible feat of heart renewal. The death of Christ is the means by which God grants us a new heart in place of our old heart.
And since Jesus Christ was in the “likeness of sinful flesh,” he became the prime candidate for a spotless sacrificial offering. That is what “for (or “concerning”) sin” means in verse 3. Jesus Christ came to take our offering upon himself. We should have received the fires of God’s wrath, but instead God himself bore our iniquities (Isa 53:4–5).
And this is how God achieves what the Law could not. And by doing so, he frees us from the guilt of sin, which leads to death, and empower us to walk by the Holy Spirit in life and peace.
The Purpose (v. 4)
We come now to our fourth and final point—which is the purpose (or goal) of verse 3. So, read again with me verse 3 and then verse 4.
“For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh, in order that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit”
Recall that I said God is righteous, and that he has a righteous requirement, which he manifested in his written code called the Law; and that those who perfectly obey this Law will experience lasting happiness and satisfaction apart from any condemnation whatsoever. Therefore, knowing this, and knowing that every man is unrighteous, the question should now arise “how is it that the righteous requirement of the Law is fulfilled in unrighteous people?”
The answer that some give, regarding verse 4, is that the Law is fulfilled because Christians walk by the Spirit—as the text clearly says. This answer is partially true, but dangerously false. If you believe that what you do achieves the Law’s impossible demands, you make yourself God, and abolish all faith in Jesus Christ, which is needed for true saving faith. You don’t walk by the Spirit and then fulfill the Law. It’s the other way around: The Law is fulfilled in you, through Jesus Christ, and then you walk by the Spirit. You mustn't get this backwards.
Many have been hurt by the church because some Christians have appeared to live a double-life. That is, they are hypocrites. In fact, I have friends who reject God because some Christian has held up his “righteous” standard only to break it moments later. You will appear like the Pharisees if you get this backwards. And Jesus called them “whitewashed tombs, which outwardly appear beautiful, but within are full of dead people’s bones and all uncleanness” (Matt 23:27).
If the Law is fulfilled in us first and then we walk by the Spirit, how is the Law even fulfilled in unrighteous sinners in the first place? Look back to verse 3. That is where we find the answer: “For God has done what the law, weakened by the flesh, could not do.” The Law is unable to make righteous those who are unrighteous through perfect obedience to the Law. Therefore, God, by sending his Son to die on the cross, made righteous those who are unrighteous. What does this mean? This means that Jesus Christ’s perfect righteousness—i.e., his perfect right standing before God—was transferred from himself and placed upon us through our faith—as if we lived his perfectly holy and God-honoring life—and that our sinfulness was transferred from us and placed upon him—as if he lived our completely unholy and God-dishonoring life (2 Cor 5:21).
And because of this, if you believe in Jesus Christ, the reality of v. 1 is for you—namely, that you will not—without any trace of doubt—experience God’s condemnation, precisely because he solved your sin problem by taking it upon himself in his death, so that you may currently live by his Spirit and then forever with him face to face. If you believe in Christ Jesus, no condemnation means,
“[You are] sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord.” (Rom 8:38–39)
So, to conclude, if you have true, saving faith in Jesus Christ, your sins are already forgiven and you are now empowered to walk by the Spirit. Don’t get that mixed up. God declares you righteous first and then empowers you to walk faithfully with heart-felt delight in his Son. When God declares you righteous in his sight, it is as if you yourself have fulfilled all the Law’s demands, even though you have not. And after this decisive moment, God begins to work on you. His Spirit is with you always, guiding you, teaching you, helping you fight sin, causing you to more deeply trust and delight in Christ. As you live, the he will grant you more and more joy in his Son as your days go on. And nothing can, or will, break that. Provided that you trust and hope and love Christ with all your heart, soul, mind and strength, there is, and there will forever be, absolutely no condemnation for you.
 John Piper, A Peculiar Glory: How the Christian Scriptures Reveal Their Complete Truthfulness (Wheaton, IL: Crossway, 2016), 170.