Missing Sunday Mass is a serious sin because you are putting something else at a higher priority than God. This is always the case unless you are physically unable to attend (e.g., illness, no transportation…). If missing mass involves full knowledge and full consent (basically you know you should go but chose not to), then it is a mortal sin. For a sin to be a mortal sin three conditions must be met (1) Grave offense – it’s seriously wrong, 2) full knowledge -I fully know it’s wrong, and 3) full consent -I freely choose to do it.
To attend Mass is a privilege, and any and all Catholics should want to attend Mass. The ability to receive Jesus in the Eucharist on Sunday at mass, is the greatest gift Jesus gave us on Earth. We should be excited to attend mass for the Eucharist.
Lastly, if someone intentionally misses Mass on Sunday or a Holy Day of Obligation, then he/she should not receive Holy Communion until he/she goes to Confession. The reason for this is because we can never receive the Body and Blood of Christ in a state of mortal sin. And to receive the Eucharist in a state of mortal sin is a mortal sin.
is something in your life that has a higher priority than God.