That depends on if you have actually been born again of the Spirit, then you are not in the flesh, but in the Spirit. The verse you quoted was Paul BEFORE becoming dead to sin. Romans 7:14-25 is Paul in the flesh, meaning he had not been born again of the Spirit yet. He had been a Pharisee at that time and all he had in his mind was the LAW. In Romans 7, ONLY verses 5-6 refer to a person that has been born again, and notice what I highlight.
5 For when we were in the flesh, the sinful passions which were aroused by the law were at work in our members to bear fruit to death. 6 But now we have been delivered from the law, having died to what we were held by, so that we should serve in the newness of the Spirit and not in the oldness of the letter.
Lizbeth, this isn't the first time I've pointed out to you the truth about Romans 7:14-25 where your verse is from (18). It really isn't that hard to remember. Go on to chapter 8 and see verse 9. "but we are not in the flesh but in the Spirit, if the Spirit of God dwells within you. And if someone does not have the Spirit of Christ, he does not belong to Him.
Where you quoted is still the ministry of death - the Law engraved on stone. Are you not going to study to make yourself approved? Don't stay stuck in the Reformation rut.
I do not agree with you here about verse 18, listing context :
Rom 7:14 For we know that the law is spiritual, but I am of the flesh, sold under sin.
Rom 7:15 For I do not understand my own actions. For I do not do what I want, but I do the very thing I hate.
Rom 7:16 Now if I do what I do not want, I agree with the law, that it is good.
Rom 7:17 So now it is no longer I who do it, but sin that dwells within me.
Rom 7:18 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.
Rom 7:19 For I do not do the good I want, but the evil I do not want is what I keep on doing.
Rom 7:20 Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me.
No unconverted reasons this way, he/she can't, the carnal mind can not, they have no idea of sin.
What Paul experienced and describing here (IMO) is the indwelling Holy Spirit talking to his conscience, one of the very first things a truly born again will experience that God is holy and he/she becomes aware that things must change. And then the battle against sin begins.
YMMV