Who do you think Paul is referring to in Rom 7:14 to verse 25? Is this a person before conversion or the present Christian experience?
These verses are definitely Paul describing, from an auto-biographical point of view, the situation of an unsaved person who is grappling with the impossibility of salvation by human works. This was an issue that must have plagued that great apostle terribly before conversion, and explains much of his zeal for persecuting the Church - he was trying to work his way into heaven through deeds he felt would be pleasing to God. But in his heart, he understood that he was sinful and committing sin in his life - a fact that made him ripe for salvation and, after turning to the Lord, for service (a humble appreciation of reality is essential to being usable by God).
The earlier context points in this direction: Rom.7:6 is contrasting our release from bondage to the law with our new freedom in the Spirit, and Paul follows with an illustration from his previous life - the truth of the law revealed his imperfections. When we arrive at verse fourteen, the beginning of the passage you ask about, Paul does use the present tense in Greek, but it is not at all uncommon in Greek prose (especially in rhetoric, philosophy, or other didactic mediums) for an author to shift into the present time in this way to portray a historical (or hypothetical) situation more vividly. His mention of being "sold under [the bondage] of sin", certainly cannot describe the situation of a believer who has been redeemed by Christ, bought out of the power and bondage of sin by His blood. And, after all, we have just been told in chapter 7:1-6 that we are now dead to sin in a manner analogous to a woman whose first husband has died. Therefore we cannot be in bondage to sin any longer - chapter 8:1-2: there is "now no condemnation for those in Christ Jesus, because the law of the Spirit has freed you from the law of sin and death".
Part of the problem is that we English readers tend to take each chapter individually, but the chapter divisions are not original and in fact are very late (they were not devised until the sixteenth century!). Paul would have been shocked to think that we were splitting chapter seven from chapter eight. Seeing these two chapters as continuing the same argument is important to understanding just what Paul is saying. Moreover, when we reach chapter eight, the Greek is a bit more helpful than the English versions, for the connection between chapters seven and eight is much tighter in Greek than in English. Chapter eight begins with ara nun ["so now on the other hand"], whereas the beginning of the last sentence in chapter seven begins with ara oun ["so then on the one hand"]. These two combinations of particles are very striking in Greek (not to mention unusual) and there can be no doubt that they are meant to be correlative, that is, paralleling and playing off each other. So that the idea in 7:25b of a person's serving two masters with mind and body pulling in different directions is being carefully and deliberately contrasted with the present reality for believers: freedom from sin in principle along with death to the sin nature (something the law could not effect, leaving well-meaning and painstakingly honest souls like pre-Paul Saul to struggle with this dual mastery of their lives). Paul continues to explain the situation for the unbeliever from an auto-biographical point of view right down to the point where he launches into the better reality for Christians in chapter eight. I translate, expanding sufficiently to bring out the biographical analogy, the transition to the new reality, and the effect of the correlative particle combinations:
(25b) So then [you can plainly see why] I myself [i.e., the previous Saul] am a slave to the God's law in my mind, but to sin's law in my body [not yet having died to sin]. (1) Now then [on the blessed other hand], there is no condemnation to those who are in Christ Jesus [and we are free, having died to sin].
Romans 7:25b - 8:1
Hope this gets to your question. For more on the whole issue of sin, treated from a variety of biblical points of view, please see Bible Basics 3B: Hamartiology: The Biblical Study of Sin. And please also see these links:
Can you recommend a good commentary on the book of Romans?
1st John 5:20 & Romans 6:23.
Yours in Christ,