Commandments of the Church

The Church has power to make commandments for Catholics (Matt 18:18).  Bishops may decide on laws for individual cases, but in the English-speaking world there are six Commandments of the Church.
1 To keep the Sundays and Holy Days of obligation holy, by hearing Mass and resting from servile work;
2 To keep the days of fasting and abstinence appointed by the Church;
3 To go to confession at least once a year;
4 To receive the Blessed Sacrament at least once a year and that at Easter or thereabouts;
5 To contribute to the support of our pastors;
6 Not to marry within a certain degree of kindred nor to solemnize marriage at the forbidden times.

Sundays and Holy Days
The Third Commandment (of God) tells us to keep holy the sabbath day.  Originally the day selected was Saturday.  This was altered by the authority of the Church to Sunday.  There are indications that Mass was celebrated on a Sunday even in the time of St Paul.
Acts 20:7:  On the first day of the week, when we were gathered together to break bread, Paul began talking to them, intending to leave the next day, and he prolonged his message until midnight.
So on Sunday we go to Mass, and refrain from our normal work activities.  This does not prevent anyone from gardening, and this is not servile work.  Nor does it prevent people from carrying out duties which are essential, such as driving buses, or doing housework.
Holy days are those set down by the Church as requiring us to go to Mass and to avoid work.  In the archdiocese of Brisbane these are Christmas Day, 25 December, and the Assumption, 15 August. 
Fasting and Abstinence
Fasting means limiting oneself to one full meal, plus two smaller meals, each day.  Abstinence means
Abstinence means doing without meat.  Fish is permitted.  The Bishops’ Conference has the power to allow alternatives such as attending Mass or saying the rosary.
Fasting applies to anyone who has reached the age of 18, but not 60.  Abstinence applies to all those over 14.
In the archdiocese of Brisbane we are required to both fast and abstain on Ash Wednesday and Good Friday. 
All Fridays throughout the year are days of abstinence, except when the Church tells us otherwise (for example when a feast occurs on a Friday).
Those who have a medical condition which would make fasting or abstinence difficult are exempt. And if fasting or abstinence would make it difficult to work, other means of mortification can be substituted.
 
Confession
The Church warns us that we need to confess our sins at least once a year.  But only if we have committed a mortal sin.  However, given the grace which is given to us in confession, it would be foolish to leave it this long, since that grace is a barrier against temptation.  The saints recommended confession once or twice a week.
In Brisbane we have seen the harm done by priests who celebrated the Third Rite, which is provided by the Church for emergencies. Each year at Easter and Christmas the people would gather in the parish church, and the priest would give absolution without confession. Over the years personal confession disappeared for most people, and Mass attendance followed.
Receiving the Blessed Sacrament
Not only does the Church require us to receive Communion at least once a year, but it specifies that we must receive the Sacrament during the period of Easter.  We are permitted to receive the Blessed Sacrament at other times of the year, and we are permitted to receive twice on the same day, provided this is at a Mass.
 
Support for our Pastors
Here we are faced with a dilemma.  We must contribute to the support of our pastors, who teach the faith, administer the sacraments, and lead the people.
But what if a priest is not performing his duties as a pastor?  For example, should we give money to Jehovah’s Witnesses who knock at the door?  If we do, we are providing support for a false religion, people who are not teaching the Catholic faith.  Since some of the money on the plate goes to support the bureaucrats who produce social justice material, it could be argued that this also is against the teachings of the Church.
Where a parish has a good priest who actually teaches the faith (this is very rare) you may want to give him some money personally, so that you are not supporting the agendas of others.
Since most priests do administer the sacraments, you could provide an appropriate amount each Sunday to satisfy your obligation to support your parish priest.
 
Marriage to Relatives, or at Special Times
Catholics cannot marry siblings, or up to second cousins, although the Church has to power to dispense from this.  The reason for this is quite obvious, and demonstrated in those societies where cousin marriage has brought about an enormous problem of deformity among children.  Marriage is not permitted between people in a direct line, such as grandfather and granddaughter or father and daughter.
There are times of the year when celebrations are limited.  Good Friday and Holy Saturday are off limits, and nuptial Masses are not encouraged during Lent and Advent.
Summary
The sacraments of the Church are no longer mentioned from the pulpit, but they are still valid.  Some years ago lists of the commandments of the Church showed an additional commandment, to send Catholic children to Catholic schools.  That was when we still had Catholic schools.