Explain the difference between sins of commission and sins of omission?

Answer 1

ommision is is a failure to do something one can and ought to do. If this happens advertently and freely, it is considered a sin.

The degree of guilt incurred by an omission is measured like that attaching to sins of commission, by the dignity of the virtue and the magnitude of the precept to which the omission is opposed as well as the amount of deliberation.

A person may be guilty of a sin of omission by failing to do something which he is able to do and which he ought to do, by reason of a cause for which he is entirely responsible, as when a person knows that drinking to drunkness will incapacitate him, and yet drinks.

Paul the Apostle refers to this sin directly when he states "For I do not do the good I want ..." (Romans 7:19)

1. The act or an instance of omitting.
2. The state of having been omitted.
3. Something omitted or neglected

[edit]this is commission