The basic idea of how we should behave in Church is summed up from the Second Council of Lyons, A.D. 1274: by POBS1
It is fitting that He Whose abode has been established in peace should be worshipped in peace and with due reverence. Churches, then, should be entered humbly and devoutly; behaviour inside should be calm, pleasing to God, bringing peace to the beholders, a source not only of instruction but of mental refreshment.
Those who assemble in church should extol with an act of special reverence that Name which is above every Name, than which no other under Heaven has been given to people, in which believers must be saved, the Name, that is, of Jesus Christ, Who will save His people from their sins.
Each should fulfil in himself that which is written for all, that at the Name of Jesus every knee should bow; whenever that glorious Name is recalled, especially during the sacred Mysteries of the Mass, everyone should bow the knees of his heart, which he can do even by a bow of his head. In churches the sacred solemnities should possess the whole heart and mind; the whole attention should be given to prayer
It doesn’t even really feel like a fast anymore since its just an hour. The Church requires every communicant to begin preparing to receive Jesus by observing an hour fast (from food) unless they’re aged or sick. Won’t really cost much to give this little to receive God into your soul would it?
Come early, recollect yourself:
Sometime ago i asked on our Facebook page “When is one late for Mass” some said with confidence “When they come later than the Sign of the Cross”. I disappointed them by reminding them that the Mass actually begins with the procession.
I usually advise people to make effort to be in Church at least 10-15 minutes before the actual time in order to have some time to pray and recollect; to begin the Mass in the right spirit. When it becomes a habit to arrive late, it ceases to be a real celebration for the person, and if it becomes a habit (especially Sundays) it begins to become sinful.
It is inappropriate to find a grown person snacking or chewing gum in Church. We want to show God some seriousness and show our devotion by setting aside a perfect “God-time”. This means we’d try to devote all our attention to the act of worship, to make it as perfect as possible. The house of God is a place of prayer, let us try to keep it so. For Children? I still don’t buy the idea of snacks. If it can be discreet, and if the child is really troublesome, then its okay.
Be modest, don’t attract too much attention by putting on something open. We also love to think Sunday as a real celebration, keep this in mind and put on the best you have. God is holy, your body is his Temple, cover it, and adorn it moderately.
No cell phones; texting, chatting, calls etc. I have seen a number of people chatting over Facebook while at Mass. Then I wonder: So we really cannot give God little time anymore?
What will it take to turn off our phones for an hour or two (Depending on where you live, some are as fast as 45 mins). The only justifiable case is big emergencies though, whatever it be, let it be serious and be discreet while attending to it. It is usually better to quietly leave the Church to attend to the emergency than text or receive calls inside.
Not even following the readings or singing the hymns from smart phones or tablets is advised. Because they are distractive to very many others merely by the flashing of their screen lights
(Those apps are for your personal edification). Besides, the hard copy Missals, Bibles and Hymn Books are blessed articles and sacramental in their nature. Aside, there’s blessing in carrying them as loads as they may be. Work yourself for Christ who carried the cross for you.
Upon entering the Church, every informed Catholic remembers that Jesus is present in the Tabernacle (usually indicated by some light beside it). The problem usually is that only few remember to show some respect. Genuflecting (such that your knee hits the ground) is a sign of devotion and reverence to the Lord who for love waits for us in the Tabernacle with
blessing and peace.
Some find it hard to follow all the routines over and over again; to stand, sit, speak when needed etc. However, active participation means exactly this. In order to be really part of a praying community, we must join the Body of Christ in its movements. We are supposed to try as much as possible to join in singing, praying, and in performing all appropriate gestures
while at Mass for our participation to be perfect.
It is customary to show some reverence before, during and after communion. Before receiving, one must recollect, pray and prepare themselves. Receiving, it is advised to bow or kneel (depending on what’s customary in your area). After receiving, kneel and pray to Jesus, don’t be in a hurry, he might also have a word or two for you. It shouldn’t be heard, it could be simple movements in your soul, inspirations etc. But pray and keep still for a while. Remember to
be joyful as well, when you leave mass, share this joy with everyone
If you’re sick, be sure not to receive from the chalice. Remember to respect people close to you, do not consider yourself alone. Your neighbor might not like to be held while at mass, or even be talked to, respect it. If your child is noisy either take them outside (if crying) or to be back. Do to others what you’d want done to you.
Don’t be in a hurry:
Do not leave the Church before the Priest (the minister), the Mass ends officially when the priest leaves the Church. Even then, it is usually advised you sit/kneel in silent prayer of thanksgiving or simply gaze at Jesus in the Tabernacle, smile at him and just be joyful. After which you should leave quietly in order not to distract others.
Do not forget to share, that we may be learning together. God bless you