"There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit." – Romans 8:1
Barnes’ Notes on the Bible:
There is, therefore, now – This is connected with the closing verses of Romans 7. The apostle had there shown that the Law could not effect deliverance from sin, but that such deliverance was to be traced to the gospel alone; Romans 7:23-25. It is implied here that there was condemnation under the Law, and would be still, but for the intervention of the gospel.
No condemnation – This does not mean that sin in believers is not to be condemned as much as any where, for the contrary is everywhere taught in the Scriptures; but it means,
(1) That the gospel does not pronounce condemnation like the Law. Its function is to pardon; the function of the law is to condemn. The one never affords deliverance, but always condemns; the object of the other is to free from condemnation, and to set the soul at liberty.
(2) there is no final condemnation under the gospel. The function, design, and tendency of the gospel is to free from the condemning sentence of law. This is its first and its glorious announcement, that it frees lost and ruined people from a most fearful and terrible condemnation.
(The first verse of this chapter seems to be an inference from the whole preceding discussion. The apostle having established the doctrine of justification, and answered the objections commonly urged against it, now asserts his triumphant conclusion, "There is therefore, etc.; that is to say, it follows from all that has been said concerning the believer’s justification by the righteousness of Christ, and his complete deliverance from the Law as a covenant, that to him there can be no condemnation. The design of Paul is not so much to assert the different functions of the Law and the gospel, as simply to state the fact in regard to the condition of a certain class, namely, those who are in Christ. To them there is no condemnation whatever; not only no final condemnation, but no condemnation now, from the moment of their union to Christ, and deliverance from the curse of the Law. The reason is this: that Christ hath endured the penalty, and obeyed the precept of the Law in their stead.
"Here," says Mr. Haldane on the passage, "it is often remarked that the apostle does not say, that there is in them (believers) neither matter of accusation, nor cause of condemnation; and yet this is all included in what he does say. And afterward, in express terms, he denies that they can be either accused or condemned, which they might be, were there any ground for either. All that was condemnable in them, which was sin, has been condemned in their Surety, as is shown in the third verse.")
Which are in Christ Jesus – Who are united to Christ. To be in him is an expression not seldom used in the New Testament, denoting close and intimate union. Philippians 1:1; Philippians 3:9; 2 Corinthians 5:17; Romans 16:7-11. The union between Christ and his people is compared to that between the vine and its branches John 15:1-6, and hence, believers are said to be in him in a similar sense, as deriving their support from him, and as united in feeling, in purpose, and destiny. (See the supplementary note at Romans 8:10.) Who walk. Who conduct, or live. Note, Romans 4:12. Not after the flesh. Who do not live to gratify the corrupt desires and passions of the flesh; Note, Romans 7:18. This is a characteristic of a Christian. What it is to walk after the flesh may be seen in Galatians 5:19-21. It follows that a man whose purpose of life is to gratify his corrupt desires, cannot be a Christian. Unless he lives not to gratify his flesh, he can have no evidence of piety. This is a test which is easily applied; and if every professor of religion were honest, there could be no danger of mistake, and there need be no doubts about his true character. But after the Spirit – As the Holy Spirit would lead or prompt. What the Spirit produces may be seen in Galatians 5:22-23. If a man has these fruits of the Spirit, he is a Christian; if not, he is a stranger to religion, whatever else he may possess. And this test also is easily applied.