In his 1996 song That's the Point, Charlie Peacock sings, "Sin is a sickness, not just a thing you do from time to time," and also, "Sin is a cancer, not just a just a thing you do from time to time." I like how that's worded, because it helps to show that there's a difference between the condition of sin (a sickness, a cancer) and the act of sin (a thing you do from time to time). To know the difference is of huge importance in understanding what the Bible says about "sin."
Two common words are translated as "sin" in the New Testament, but have different meanings (as represented above). The two words are hamartano (verb) and hamartia (noun).
Harmartano (verb) means "to miss the mark" in the sense of actual sinful behavior ("a thing you do from time to time").
Hamartia (noun) can also mean "to miss the mark," but in a different sense. It's the inward condition (not the action) that is off the mark. Hamartia can also mean "a governing principle or power," which I'll touch on briefly in a bit.
(There are also other related words that describe "sin," but at the moment they don't apply to this particular discussion).
It's interesting (and important) to note that Paul uses one of these two words far more predominantly than he uses the other one. Do you know which one it is? In the entirety of his epistles, he uses Hamartano (verb) only 14 times, compared to an astounding 55 uses of Hamartia (noun). What's more, most of Paul's uses of these two words are in the book of Romans, where the ratio is even more astounding: 6 uses of Hamartano (verb), compared to 39 uses of Hamartia (noun)! Let me put it this way. Most of the time we see the word "sin" in Romans, Paul is not talking about sinful behavior, but about the sin condition. Again, this is utterly important when it comes to understanding what Paul is talking about throughout the epistle.
Part 3 of my recent "Christ Is the End of the Law" series was about Paul's words in Romans 5 and 7, in which he writes about the "sinful passions which were aroused by the law" and in which he describes how when the law came, sin "abounded." One of my points in that post is that the wording of these phrases is a bit misleading. It makes it seem as if the amount of this thing called "sin" actually increased or abounded, and as if the law increased the desire in people to behave sinfully.
But that's not what Paul is saying at all. Please read that whole post to get the full gist of what I was saying, but in short I'll say this: In the phrase "sinful passions which were aroused by the law," the word "passions" is a word that really means "hardship," "affliction," "pain" or "suffering." Also, the word "aroused" was added by translators. One could then translate the phrase as "the affliction of sin which is by the law." The condition of sin was already in the world before the law came, but it wasn't known as "sin," and without the law sin could not be imputed to man.
Sin was "aroused" (although again, that word was added by translators) and sin "abounded," not in that the condition became worse, and not in that it caused an increase in sinful behavior, but in that when the law came, sin was suddenly shown to be sin (Rom 7:13) and could now be imputed to man (put on man's account) (Rom 5:13).
So now to the point of this post. Not one of those instances of the word "sin" (sin abounded, sin increased, sin "aroused" by the law, etc) is talking about the act of sin (sinful behavior). It's talking about the condition of sin. The sickness of sin. The cancer of sin. Now it's true that the condition of sin was the reason for the acts of sin. Sinful acts show that the sin condition is there. But... the law didn't come to impute the acts to man. It came to make the condition known and to impute the sin condition to man. "Sinful acts" didn't (and don't) abound through the law. Rather, the sin condition abounded. Again (and this is very important!), not meaning that the sin condition grew or became worse, but that the sin condition, which was already in the world before the law, was revealed to be the sin condition that it was. The sin condition was aroused by the law. Again (important!), not meaning that the law caused sinful behavior to be aroused, but that it exposed the sin condition, which was already in the world before the law, for what it was.
The problem was never "sinful behavior." Sinful behavior - "a thing you do from time to time" - was a symptom of the actual problem - the sin condition. The "actual problem" is what the law exposed. A person can have the symptoms of cancer without even knowing they have cancer. The symptoms can be known and treated, but that doesn't take care of the cancer. What needed to take place was that the cancer itself needed to be exposed for what it really was, and condemned for what it was, and "imputed" for what it was, and then it could be dealt with once and for all. The law came to expose sin (the condition of sin) and to condemn it for what it was, but the law didn't actually take away the problem.
The ministry of the law led TO the ministry of Christ. The ministry of the law was that it imputed sin to all of mankind - from Adam to the very last person ever born on earth! The law doesn't keep doing this on an ongoing basis, for each individual person at some point in their life. It did its job once, imputing sin to all of mankind once and for all, and then it died. It was nailed to the cross, making way for the ministry of Life - Jesus Christ Himself.
"But the Scripture (the law) has confined all under sin, that the promise by faith in Jesus Christ might be given to those who believe." (Gal 3:22)