Many people understand why we should keep the 10 Commandments but seem to have a misunderstanding of the sins of omission.

Things we should be doing but fail to do fall under this category. Visiting the sick may be an example of a good Christian work. Failing to do this may fall under the sin of omission. Also helping a sick person that needs help, even being an organ donor, may be another example of a Christian thing to do.

I am starting to see the logic of including the Denial of the Holy Eucharist. Once we are given the Gift of Life, our greatest Gift from God is the Holy Eucharist.  Accepting and Receiving this Gift is the obligation of every Christian.

Denying this Gift may fall under the sin of omission. In the words of St. Ignatius of Antioch, "They who deny the Holy Eucharist are perishing in their disputes".

Please check my article on St. Ignatius of Antioch for more details.

There are 20M-25,000,000 fallen away Catholics that have turned away from the Holy Eucharist and may even deny in the True Presence. This Gift from God has been given to us to accept and consume. That is the entire meaning of John 6:51-68.

By walking away and not partaking in the Holy Eucharist, they are omitting what is expected of them. Yes we have a Free Will but, I believe, this rejection falls under the Sin of Omission.