Good Question

When the Bible says we will be accountable for all of our actions, does that include sins that we've already been forgiven for?

Response is from RC Sproul.  Some deep thoughts here.

I think so. Some people will be quick to point out that the Bible says, "As far as the east is from the west, so far has God removed our transgressions from us" and that he has cast them into the sea of forgetfulness. When God forgives us of our sins, he forgets them. He remembers them no more against us. So it would seem that we could conclude from those passages that once we are forgiven of a sin, that's the absolute end of it and we never have to be held accountable for it.

When we are forgiven by God for a sin, there are two things we have to understand. First of all, when the Bible speaks of God's forgetting our sins, we have to be careful how far we push that. That does not mean that suddenly the eternal God, very God of very God, who is omniscient and immutable, suddenly undergoes a memory lapse and that that which he once knew intimately he suddenly becomes ignorant of. If we push that, it would give us a ghastly view of God. Rather, the Bible is using this kind of language to say that he doesn't hold it against us anymore. He treats us without raising the issue in terms of delivering a punishment. The just punishment for any sin would be eternal separation from God. When we are forgiven, we are relieved of all eternal guilt and punishment so that we don't have to worry about going to hell because we have sinned.

At the same time, the New Testament tells us at least twenty-five times that the distribution of rewards in heaven will be done according to our relative degree of obedience or the works that we perform. We are told frequently by Jesus that on the last day all things will be brought into the light. Those things we have done in secret will be made manifest; every idle word will come into the judgment. I don't think that means that I'm going to be punished for those sins that I've confessed and have had forgiven. Those are covered by the righteousness of Christ and by my Mediator. But I will have to stand before God for a full and complete evaluation of my obedience as a Christian.

Whether or not at that time of evaluation he will mention the complete track record or just say, "Here's the bottom line, you'll get so many rewards"—I don't know how that's going to work. But I am going to be brought into a final accounting, and certainly in God's mind every detail of my life will be there. Even though I am forgiven and I am not punished, any sin still means that I will receive less reward than if I had been obedient.