Why Must I Attend Sunday Mass?

Jesus said, "Do this in memory of me" (Lk. 22:19) at the Last Supper. The only way I can fulfill this command is by attending Mass.

Jesus said, "Amen, amen, I say to you, unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you" (Jn. 6:53). To have no "life within you" is to be without sanctifying grace, which is necessary for friendship with God, and ultimately, for salvation. May you receive the Eucharist (the flesh of Jesus) if you don't attend Sunday Mass regularly? No because:

It is a serious sin to miss Mass on Sundays or holy days. The Catechism of the Catholic Church teaches:

On Sundays and other holy days of obligation the faithful are bound to participate in the Mass...The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to particpate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor. Those who deliberately fail in this obligation commit a grave sin.

 

Thus, you cannot receive the Eucharist worthily if you don't attend Sunday Mass weekly, since being in grave sin means that you may not receive the sacraments. if you are in grave sin, you must go to confession before receiving the Eucharist again.

The third commandment is still in effect: "Keep holy the Lord's day." What could be holier than the Mass? The Mass sanctifies our Sundays and holy days.

"From the liturgy...especially from the Eucharist, grace is poured forth upon us as from a fountain, and the sanctification of men in Christ and the glorification of God to which all other activities of the Church are directed, as toward their end, are archieved with maximum effectiveness." (Vatican II)