To be more precise Paul is saying that before he realized that he had sinned he had sinned:
"Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet. But sin, taking occasion by the commandment, wrought in me all manner of concupiscence. For without the law sin was dead. For I was alive without the law once: but when the commandment came, sin revived, and I died" (Ro.7:7-9).
First, the context for this statement is whether or not the law can either justify or sanctify a person. In Romans 7:1-5 Paul claims that the child of God is dead to the law through the body of Christ. So his short answer is no, the law cannot do either.
In Romans 7:6-13 he proves the proper function of the law is to REVEAL the true condition of a man rather than provide life and the problem is not in the law but in man.
Now, note how he opens verse 7 "Nay, I had not KNOWN sin but by the law." The purpose of the law is to reveal to man what he DOES NOT KNOW! There as a time that Paul did not KNOW he was a sinner. That does not mean he wa not a sinner but he merely didn't KNOW he was a sinner.
If you do not perceive yourself as a sinner than what is your perception of yourself? There are many religious people, full adults, who do not know they are sinners. Some even believe they live above sin. Others believe they will go to heaven because they see themselves as basically good as anyone else. We know this is precisely how Paul perceived himself as a RELIGIOUS ADULT because he says so to the Philippians:
Philip. 3:4.....
If any other man thinketh that he hath whereof he might trust in the flesh, I more: 5 Circumcised the eighth day, of the stock of Israel, of the tribe of Benjamin, an Hebrew of the Hebrews; as touching the law, a Pharisee; 6 Concerning zeal, persecuting the church; touching the righteousness which is in the law, blameless.
Hence, in Romans 7 he is speaking of himself as a DEVOUT RELIGOIUS ADULT highly trained in the Law. However, he lived in SPIRITUAL BLINDNESS, dead in sin but IGNORANT of it!
However, there came a point when the Holy Spirit took the Law and used it to reveal that he was not "blameless" concerning the righteousness of the law but was a VIOLATER of the law. At that precise point he went from self-perception as ALIVE under the law to being condemned of sin, thus DEAD under the Law. His actual SPIRITUAL DEADNESS had not changed at all but his KNOWLEDGE of his SPIRITUAL DEADNESS had changed. He had not changed from a sinner to a sinner in reality but only in regard to his own experiential KNOWLEDGE of himself.
"Without the law" meaning without this new KNOWLEGE provided by the Law he had been alive unto God as he saw his religious self, "blameless" in his own sight and thus justified by law for eternal life. However, when this KNOWLEGE provided by the law came his self perception as "BLAMELESS" was destroyed and he his indwelling sin nature revealed its ugly self and he went from "blameless" to condemned unto death in regard to his own KNOWLEGE.
When this KNOWLEGE of the law came, "I died" under the knowledge of revealed sin because it condemned him as a sinner and so his self-perception as "BLAMELESS" was changed.
Now, you won't accept this interpretation even though it is correct because you have an agenda to defend and because you are spiritually blind to this truth. However, I will let the readers come to their own conclusion whose interpertation is correct!
Of course when Paul said he "died" he was referring to spiritual death because he was still alive physically when he wrote those words. He knew that he died spiritually when he coveted even though at that time he did not even know that it was a sin.
Yes he was speaking of his own spiritual death. He simply came to the KNOWLEGE of his spiritual death at that point! He went from seeing himself as "BLAMELESS" under the law as a fully trained Religous Phariseeical Rabbi, to the realization he was and had been really SPIRITUALLY DEAD and just did not KNOW it! Nothing changed in his spritual status but his KNOWLEGE of it!
From this we can know that Paul was not born spiritually dead because a person must be alive spiritually before he can die spiritually as a result of sinning. Paul, as well as you and I, are born spiritually alive.
No, he simply came to KNOW by the Law his true spiritual condition since birth. He had died in Adam when Adam sinned -
"
through the offence of one many BE dead" - Rom. 5;15
Ignorance of sin does not mean you are not a sinner. The Law reveals what you really are:
"
Nay, I had not known sin, but by the law"
His attaining knowledge of it did not change anything but his own perception of himself. He was conceived in sin from his mother's womb and foolishness was "bound up in his heart" as a child from his mother's womb. His sinfulness was apparent to his parents because they had to DISCIPLINE him in order to "train him up in the way he ought to go" because he was sinful by nature and no training was necessary for him to do wrong! It came naturally by birth.