In Romans 7 Paul is speaking from the vantage point of one who is under the Law. Paul’s statements are not about his lack of power to deal with sin now that he has come to Christ. Instead, these words are a part of his expounding on the Law and grace and the effects the Law has on a person in the flesh without the grace of Christ.
In Romans 8, Paul says “the law was weak through the flesh.” The Law can only bring the sinner under condemnation, but grace gives us victory over sin and condemnation.
Throughout the entirely of Romans 6 Paul shows how the one who has received saving grace is dead to sin through Jesus Christ, and therefore sin is not to reign over them.
In Titus 2:11-15 Paul says that saving grace teaches us to deny ungodliness and worldly lusts by living soberly, righteously, and godly in this present world. Saving grace does not teach us that we cannot overcome sin. Saving grace teaches us how to overcome sin.
In 2 Timothy 2:19 Paul tells us the following:
Nevertheless the foundation of God standeth sure, having this seal, The Lord knoweth them that are his. And, let everyone that nameth the name of Christ depart from iniquity.
In 1 Thessalonians 4:2-7 Paul says:
2 For ye know what commandments we gave you by the Lord Jesus.
3 For this is the will of God, even your sanctification, that ye should abstain from fornication:
4 That every one of you should know how to possess his vessel in sanctification and honour;
5 Not in the lust of concupiscence, even as the Gentiles which know not God:
6 That no man go beyond and defraud his brother in any matter: because that the Lord is the avenger of all such, as we also have forewarned you and testified.
7 For God hath not called us unto uncleanness, but unto holiness.
In Romans 7 Paul, as a skillful teacher, speaks figuratively from the vantage point of one who is under the Law, to explain the influence that the Law has on the one who is under the bondage of sin. The Law had no power to give life to the one entrapped in his sins. Only Christ Jesus can set a person free from sin.
1 There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.
2 For the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death.
3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
The law was weak through the flesh and therefore could not deliver man from his sins, and this is exactly what Paul in explaining in Romans 7:7-25, as he speaks from the vantage point of the effects of the law on those who are under it’s condemnation.