There is a Book of Common Worship prayer of confession of sin that asks for forgiveness for "those things that we have done that we ought not to have done and for those things that we have not done that we ought to have done." The two kinds of sins: the sin of commission and the sin of omission.
There are glaring examples of both in the news at the moment. There is a horrific example of the sin of commission in the act of the shooter in Colorado. One twisted and evil man goes to a movie theater and does an incredible evil act. We will talk about what caused him to act that we. We will talk about what we could do to prevent others from acting that way. We will talk about the wisdom of banning assault weapons from individuals. We will have lots of discussions of how and why one intelligent young man became a vicious killer, but this was a sin of commission by an individual. The pain and suffering that one act of commission is almost more than the mind can comprehend.