Confession Before Communion if I Missed Mass?

Q. Do I need to go to confession before taking Communion if I miss Sunday Mass due to going on vacation?

A. Yes, most likely, at least an honest attempt must be made, but let’s clarify.  It’s not necessarily a black and white answer.

The quick answer is that if you committed a mortal sin, then yes, you should go to confession prior to receiving Holy Communion if possible.  But let’s look at this in more detail.

The first question is this:  Have you committed a mortal sin?  Well, if you did a grave action, you had full knowledge that it was seriously wrong, and you did it anyway with complete consent of the will, then, yes, you committed a mortal sin.  If one of these three factors was lacking, then it may still be a grave violation of God’s law, but you may not be morally culpable for your actions (See Chapter 2 – The Law, Society, Grace and Salvation for a more thorough explanation).

Let’s look at these three factors in regards to your question:

1. Is it grave matter to miss Sunday Mass?  Yes it is.  It’s a violation of the Third Commandment.
2. Did you have full knowledge that this was a grave violation?  This is for you to decide.  After reading this you certainly do, but what about prior to reading this?  What was your honest understanding?  If you were ignorant of this command from our Lord, through no fault of your own, then your guilt for missing Sunday Mass may have been lessened.
3. Did you miss the Mass with full consent of the will?  For example, if you were driving there and your car broke down, you did not intentionally miss Mass.  In this case, it’s not a mortal sin and may not even be a sin at all even though the Third Commandment was violated in an objective sense.

What’s important to understand is that for a sin to be mortal, and therefore exclude us from receiving Holy Communion, we must be fully guilty of the action.  God knows the full picture and will judge accordingly.  Be honest with yourself and with God and admit your guilt when it is there.  Do not be afraid to refrain from Communion if you are aware of serious sin and have not chosen to confess it yet.  Refraining, in this case, is far better for your soul than going to Communion.

With that said, Canon Law does allow for someone who has committed grave sin to receive Communion under certain conditions.  The canon says this:

Can. 916 A person who is conscious of grave sin is not to celebrate Mass or receive the body of the Lord without previous sacramental confession unless there is a grave reason and there is no opportunity to confess; in this case the person is to remember the obligation to make an act of perfect contrition which includes the resolution of confessing as soon as possible.

That an act of perfect contrition, with certain other conditions, is enough to dispose you to receive Communion after committing a mortal sin and before confessing it.  For example:

1. You committed a grave sin,
2. You have a perfect contrition for that sin (meaning true sorrow flowing from your deep love of God),
3. You cannot get to a priest for confession prior to Sunday,
4. There is a “grave reason” that you are compelled to receive Communion that day,
5. You make a firm resolve to confess this grave sin the next time you have the reasonable opportunity,
6. Then the grace of the Sacrament has already begun to pour forth and you should go to Communion.

The best advice to offer is to avoid mortal sin and all will be well!

(Taken from Catholic Q & A)

Answers to previous five queries

Why Do I Need To Confess To A Priest?

Should I Confess My Past Sins?

Why Confession? 

What is an Indulgence? 

Losing Faith in God?