Sins of commission relate to the actions we do which we should not have done. Sins of omission relate to the things we should have done that we did not do.
Often the greatest flaws of churches is the failure to act. We feel that many things are not our issue. We try to act as if the law tells us only what not to do rather than also commanding us to positively act.
Often the reality is we make our responsibility too small. We are often too narrow with the law.
The law requires far more than we wish to think. It requires that we act even when we do not feel comfortable.
It asks many things of us which push us much farther than we feel is reasonable. And that is why you see a lot of the teachings of scripture ignored.
It isn't so hard to ignore scripture: we often listen to the words and feel a bit convicted and then walk away and forget the issue. But to really live out our faith well we sometimes need to act.
I suppose understanding the law in it's depths is frightening. But the reality is always that there is more grace in God than sin in us.
We need to rest in the true depths of Christ's love. And resting in that deep grace is what enables Christian living, not hinders it.