The Catholic Church teaches that we have an obligation to go to Mass every Sunday. Mass is a celebration of the Eucharist. Many people do not understand why the Church requires Mass every Sunday. The answer is found within the Ten Commandments passed on to Moses several millennia ago.
The Ten Commandments, which were the believed to be the laws and moral code handed down by God, tells believers in the Third Commandment to "Remember to keep holy the Sabbath day."For the Christians, the Sabbath was Sunday, which was the day of Jesus Christ's resurrection from the dead. The Church says that you have an obligation to fulfill the Third Commandment by refraining from unnecessary work on Sunday and by participating in Mass, your chief form of worship as Christians.
The Catechism of the Catholic Church states that "You shall attend Mass on Sundays and holy days of obligation and rest from servile labor." The obligation is binding every Sunday. It is a holy day of obligation, a day for you to grow in your faith, and you are required to attend to the extent that you are able to do so.
Private Worship is Not Enough. From the earliest days of the Church, Christians have understood that being a Christian is not a private matter. You are called to be Christians together. While you should engage in the private worship of God throughout the week, your primary form of worship is public and communal, which is why Sunday Mass is so important.
Fr. David