16. The celebration of Mass, as the action of Christ and the People of God arrayed hierarchically, is the center of the whole Christian life for the Church both universal and local, as well as for each of the faithful individually.22 In it is found the high point both of the action by which God sanctifies the world in Christ and of the worship that the human race offers to the Father, adoring him through Christ, the Son of God, in the Holy Spirit.23 ...Furthermore, the other sacred actions and all the activities of the Christian life are bound up with it, flow from it, and are ordered to it.25
...the "high point both of the action by which God sanctifies the world in Christ and of the worship that the human race offers to the Father...."
22. The celebration of the Eucharist in a particular Church is of utmost importance.The Chapter III continues with the section called" The People of God, mentions:
II. The Duties of the People of God
95. In the celebration of Mass the faithful form a holy people, a people whom God has made his own, a royal priesthood, so that they may give thanks to God and offer the spotless Victim not only through the hands of the priest but also together with him, and so that they may learn to offer themselves.83 They should, moreover, endeavor to make this clear by their deep religious sense and their charity toward brothers and sisters who participate with them in the same celebration.
Thus, they are to shun any appearance of individualism or division, keeping before their eyes that they have only one Father in heaven and accordingly are all brothers and sisters to each other.
96. Indeed, they form one body, whether by hearing the word of God, or by joining in the prayers and the singing, or above all by the common offering of Sacrifice and by a common partaking at the Lord's table. This unity is beautifully apparent from the gestures and postures observed in common by the faithful.
I went searching for more specific direction on Mass dress codes and found:
Online Edition - Vol. VI, No. 8: November 2000. "Dress, Demeanor, Discipline
Show how We Value Holy Mass" by Bishop Robert Vasa. In his paper, he writes:
Several years ago, the Holy Father reinstituted a dress code for the churches of Rome, his diocese. No one in shorts or sleeveless shirts was to be admitted into the church building
An American sense of rights and freedom rebels against such rules, calling them absurdities. Yet it was done and it was enforced. Tourists who had traveled across an ocean to see a church were turned back at the door unless they were properly attired. This was only to visit a church while no other liturgical action was going on. The Holy Father saw a need to institute a policy aimed at restoring, in a very concrete way, a proper sense of reverence for the house of God..
I have often heard the argument that the administrators of churches should be pleased to see that people come, regardless of how they are dressed. The other side of that is that people need to demonstrate in word and deed the proper disposition and attitude. I am certain the American people would be rightfully chagrined if the guard at the Tomb of the Unknown Soldier were to show up in plaid shorts, a tank top and half-laced tennis shoes. It is hard to imagine that he could have a proper interior attitude to the job at hand were he to come to "work" dressed like that.
Our liturgy is a sacred "work". How we come to that work is probably as important as the fact that we come. We must recognize that we come to church for sacred work, sacred worship. This demands a decorum commensurate with the dignity of the work to be done. Even if that "work" is to utter a private prayer, it still demands an appropriate decorum.
The soldiers at Arlington know the sacredness of the work which they do. Their dress, their demeanor, their discipline all speak of their recognition of that sacredness. Seeing them is a source of pride for me.
I am proud of what they represent, proud of the values which their discipline bespeaks, proud of the country which at heart still knows that honor and fidelity are worth defending.
For these values people live, and for these values people give their lives. The dress and demeanor of these troops says that they truly honor and respect the life and death of those represented at the Tomb of the Unknown.
Catholics likewise need to know the sacredness of the liturgical "work" which they do. Their dress, their demeanor, their discipline, ought all to speak of their recognition of that sacredness.
Seeing the dress and demeanor of Catholics in Church ought to be a source of pride. They ought to manifest a genuine respect for Jesus present, as well as for the values of the Catholic Church. For these values, saints, declared and not declared, gave their lives; for these values each Catholic must be willing to dress in a fashion which shows recognition and respect.
If the Catholics that wear picnic clothes, untucked shirts, shorts, and flip flops to church on Sunday really knew what they were doing, where they were going, and for whom...would they dress this way? If the president of the United States were to visit, or the Pope, would we show up in shorts and t=shirt? If Christ Himself were to announce that He was going to be at our Church this Sunday, would we show up in spaghetti-strap dresses and crocs?
In the parish my family belonged to (and miss terribly) in Texas, I went through the Eucharistic Ministry training. Deacon Don instructed us to a specific dress code. Men were to wear dress slacks and a sport coat with a tie, women were to wear dresses, skirts, and pants only if part of a pantsuit set. Neat hair, and as a Eucharistic minister, we are to live a life outside the Church that reflected our ministry.
Not only as a Eucharistic Minister is one serving the priest, they are serving God and His people. Children see these folks up at the altar as special people with a special task. Eucharistic Ministers are examples of what God's people look like in the service of the altar.