"II. THE PRECEPTS OF THE CHURCH
2041 The precepts of the Church are set in the context of a moral life bound to and nourished by liturgical life. The obligatory character of these positive laws decreed by the pastoral authorities is meant to guarantee to the faithful the very necessary minimum in the spirit of prayer and moral effort, in the growth in love of God and neighbor:
2042 The first precept (“You shall attend Mass on Sundays and holy days of obligation and rest from servile labor”) requires the faithful to sanctify the day commemorating the Resurrection of the Lord as well as the principal liturgical feasts honoring the mysteries of the Lord, the Blessed Virgin Mary, and the saints; in the first place, by participating in the Eucharistic celebration, in which the Christian community is gathered, and by resting from those works and activities which could impede such a sanctification of these days.82
The second precept (“You shall confess your sins at least once a year”) ensures preparation for the Eucharist by the reception of the sacrament of reconciliation, which continues Baptism’s work of conversion and forgiveness.83
The third precept (“You shall receive the sacrament of the Eucharist at least during the Easter season”) guarantees as a minimum the reception of the Lord’s Body and Blood in connection with the Paschal feasts, the origin and center of the Christian liturgy.84
2043 The fourth precept (“You shall observe the days of fasting and abstinence established by the Church”) ensures the times of ascesis and penance which prepare us for the liturgical feasts and help us acquire mastery over our instincts and freedom of heart.85
The fifth precept (“You shall help to provide for the needs of the Church”) means that the faithful are obliged to assist with the material needs of the Church, each according to his own ability.86
The faithful also have the duty of providing for the material needs of the Church, each according to his own abilities.87
"
vatican.va/archive/ccc_css/archive/catechism/p3s1c3a3.htm
In that case- I would send it, but better yet, I would firstly doubt that the priest said that, ask who it was, talk to the priest, to see. After that, I would look at what some other things say such as (including what I started with)-
newadvent.org/cathen/14335a.htm
"It is both a precept of the Church and Church law that Catholics must worship God on Sunday and Holy Days of Obligation by participating in the Holy Mass. This follows from the fact that in the Mass it is Christ Himself who worships the Father, joining our worship to His. In no other way is it possible to adequately give thanks (eucharistia) to God for the blessings of creation, redemption and our sanctification than by uniting our offerings to that of Jesus Christ Himself. Following the example of the Old Covenant the Church does this weekly, on the day of the Lord’s Resurrection.
Code:
Canon 1247
On Sundays and other holy days of obligation the faithful are bound to participate in the Mass; they are also to abstain from those labors and business concerns which impede the worship to be rendered to God, the joy which is proper to the Lord's Day, or the proper relaxation of mind and body.
Canon 1248
1. The precept of participating in the Mass is satisfied by assistance at a Mass which is celebrated anywhere in a Catholic rite either on the holy day or on the evening of the preceding day.
2. If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the liturgy of the word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families.
Since a “grave cause” is needed to excuse one from this obligation it would be a serious or mortal sin to willfully skip Mass on Sunday or a Holy Day of Obligation, as the Church has always taught. Reasons such as the necessity to work to support one’s family, child care, personal sickness or the care of the sick, necessary travel etc. would excuse a person on a particular occasions. Those who have continuing reason to be excused should consult their pastor."
ewtn.com/expert/answers/sunday_mass.htm
Vatican says
"The Sunday obligation
2180 The precept of the Church specifies the law of the Lord more precisely: "On Sundays and other holy days of obligation the faithful are bound to participate in the Mass."117 "The precept of participating in the Mass is satisfied by assistance at a Mass which is celebrated anywhere in a Catholic rite either on the holy day or on the evening of the preceding day."118
2181 The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate 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.119 Those who deliberately fail in this obligation commit a grave sin.
2182 Participation in the communal celebration of the Sunday Eucharist is a testimony of belonging and of being faithful to Christ and to his Church. The faithful give witness by this to their communion in faith and charity. Together they testify to God’s holiness and their hope of salvation. They strengthen one another under the guidance of the Holy Spirit.
2183 "If because of lack of a sacred minister or for other grave cause participation in the celebration of the Eucharist is impossible, it is specially recommended that the faithful take part in the Liturgy of the Word if it is celebrated in the parish church or in another sacred place according to the prescriptions of the diocesan bishop, or engage in prayer for an appropriate amount of time personally or in a family or, as occasion offers, in groups of families."120 "
vatican.va/archive/ccc_css/archive/catechism/p3s2c1a3.htm
Vatican on those canons
vatican.va/archive/ENG1104/_P4N.HTM
Send them this, Marc.
