The Mass Explained

Once the people are gathered, the priest and ministers approach the altar while the Entrance Chant is sung. On reaching the sanctuary, the priest and deacon venerate the altar with a profound bow and a kiss, and, when incense is used, the priest incenses the cross and the altar.

The entrance opens the celebration, fosters the unity of those gathered, introduces their minds to the mystery of the liturgical season or festivity, and accompanies the procession of the ministers. The kiss of the altar expresses reverence for Christ, whom the altar signifies.

When the Entrance Chant is concluded, the priest and the faithful, standing, sign themselves with the Sign of the Cross. The priest then greets the assembled people with one of the approved formulas (e.g., 'The grace of our Lord Jesus Christ…'), and the people reply, 'And with your spirit.'

The sign and the greeting signify the presence of the Lord to the assembled community. By this greeting and the people's response, the mystery of the Church gathered together is made manifest.

The priest invites all to recall their sins. After a brief silence, the community makes a common act of penitence — most often the Confiteor ('I confess to almighty God…') — followed by the priest's absolution ('May almighty God have mercy on us…'). Formulas B and C are also provided in the Missal.

The Penitential Act prepares the faithful to celebrate the sacred mysteries with pure hearts. The priestly absolution pronounced here, however, lacks the efficacy of the Sacrament of Penance — it does not remit grave sin, for which sacramental confession remains necessary.

Unless the Kyrie has already been included in the Penitential Act, it follows directly. Each acclamation ('Lord, have mercy… Christ, have mercy… Lord, have mercy') is ordinarily said twice, though the number may vary depending on the musical setting.

The Kyrie is a chant by which the faithful acclaim the Lord and implore his mercy. Because it is a song, it is ordinarily to be sung by all, involving the people and the choir or cantor.

The Gloria ('Glory to God in the highest…') is sung or said on Sundays outside Advent and Lent, on Solemnities and Feasts, and at particular celebrations of a more solemn character. It may be intoned by the priest, cantor, or choir and is sung either by all together, by the people alternating with the choir, or by the choir alone.

The Gloria is a most ancient and venerable hymn by which the Church, gathered in the Holy Spirit, glorifies and entreats God the Father and the Lamb. The text of the hymn may not be replaced by any other text.

The priest invites the people to pray with the words 'Let us pray.' All pray silently for a brief time, after which the priest, with hands extended, says the Collect proper to the day. The people make the prayer their own by the acclamation 'Amen.'

Through the Collect the character of the celebration is expressed; the priest's prayer, gathering up the silent petitions of the faithful, is addressed to God the Father, through Christ, in the Holy Spirit, and concludes with a Trinitarian ending.

The reader goes to the ambo and proclaims the First Reading, to which all listen seated. At the end the reader acclaims 'The word of the Lord,' and the people respond, 'Thanks be to God.' A brief silence may follow.

In the readings, the table of God's Word is spread before the faithful, and the treasures of the Bible are opened to them. When Sacred Scripture is read in the Church, God himself speaks to his people, and Christ, present in his word, proclaims the Gospel.

The psalmist or cantor sings the verses of the Psalm at the ambo, while the whole congregation sits and listens, normally taking part by means of a response. The Psalm is ordinarily taken from the Lectionary.

The Responsorial Psalm is an integral part of the Liturgy of the Word and holds great liturgical and pastoral importance, fostering meditation on the Word of God. It is preferably sung, at least as regards the people's response.

On Sundays and Solemnities a Second Reading, taken from the Apostle (the Letters or Revelation), is read from the ambo and concluded in the same way as the First Reading.

The use of a second reading on Sundays and Solemnities provides a richer share of God's Word and reflects the Church's desire, renewed by the Council, that the treasures of the Bible be opened more lavishly to the faithful.

After the Second Reading, the Alleluia or another chant laid down by the rubrics is sung, as the liturgical season requires. All stand. During Lent, a Gospel Acclamation replaces the Alleluia.

The Alleluia or the Verse before the Gospel constitutes a rite or act in itself, by which the assembly of the faithful welcomes and greets the Lord, who is about to speak to them in the Gospel, and professes their faith by singing.

The deacon (or, in his absence, the priest) goes to the ambo, accompanied if appropriate by ministers with incense and candles. He greets the people, announces the Gospel while signing the book and himself, and proclaims the reading. At the end he kisses the book.

The reading of the Gospel constitutes the high point of the Liturgy of the Word. The Liturgy itself teaches the great reverence to be shown to this reading by setting it off from the other readings with special marks of honor: incense, candles, acclamations, and a minister of higher rank.

The Homily is given by the priest celebrant or, at times, by a concelebrating priest or by the deacon, but never by a lay person. It is required on Sundays and Holy Days of Obligation and commended on other days.

The Homily is part of the Liturgy and is highly recommended: it is necessary for the nurturing of the Christian life. It should be an exposition of some aspect of the readings from Sacred Scripture or of another text from the Ordinary or the Proper of the Mass of the day.

On Sundays and Solemnities, the Nicene-Constantinopolitan Creed is recited by all, standing. The Apostles' Creed may be used, especially during Lent and Easter Time. All bow at the words 'and by the Holy Spirit… and became man'; on the Nativity and Annunciation, all genuflect.

The Creed is meant to respond to the Word of God proclaimed in the readings and homily and to call to mind and confess the great mysteries of the faith before their celebration in the Eucharist.

The priest introduces the prayer from the chair; intentions — normally for the Church, civil authorities, those burdened by various needs, and the local community — are announced from the ambo or another suitable place. The priest concludes with a prayer.

In the Universal Prayer, the people, exercising their priestly function, intercede for all humanity. It is a response to the Word of God just received in faith, by which the people offer prayers for the salvation of all.

An Offertory Chant accompanies the procession. The bread and wine, with a little water added to the chalice, are brought to the altar; the priest prays the two Berakah-style prayers ('Blessed are you, Lord God of all creation…'). He may incense the gifts, the cross, and the altar, and is himself incensed along with the people.

The bread and wine become the matter of Christ's Body and Blood. The gifts of the faithful express their participation in the offering and symbolize the work of human hands presented to God for transformation.

After the invitation 'Pray, brethren…' and the people's response ('May the Lord accept the sacrifice at your hands…'), the priest, with hands extended, says the Prayer over the Offerings. The people acclaim 'Amen.'

This prayer gives the Preparation of the Gifts its conclusion and disposes the faithful for the Eucharistic Prayer that is about to begin. The Church asks that the gifts, and with them the Church's offering of herself, be accepted by the Father.

The Eucharistic Prayer comprises the Preface (thanksgiving), Sanctus, Epiclesis (invocation of the Spirit), Institution Narrative and Consecration, Anamnesis (memorial), Oblation, Intercessions, and Final Doxology with the Great Amen. The people join in the Sanctus, the Memorial Acclamation, and the Great Amen.

The Eucharistic Prayer is the center and high point of the entire celebration — the prayer of thanksgiving and sanctification. Its meaning is that the whole congregation joins Christ in confessing the great deeds of God and in offering the Sacrifice. The priest alone speaks in the name of the whole holy people.

Within the Eucharistic Prayer, the priest pronounces the words Jesus spoke at the Last Supper: 'Take this, all of you, and eat of it… This is my Body… This is the chalice of my Blood…' He then genuflects in adoration after each consecration, and the consecrated elements may be elevated for the people to see.

By the power of the words of Christ and the invocation of the Holy Spirit, the bread and wine are changed — transubstantiated — into the Body and Blood of Christ. This is the heart of the Eucharistic Sacrifice and the source of the Mass's efficacy.

The priest invites the faithful to pray, and all — standing — recite or sing the Pater Noster together. The priest adds the embolism ('Deliver us, Lord, we pray…'), and the people conclude with the doxology 'For the kingdom, the power, and the glory are yours…'

In the Lord's Prayer, a petition is made for daily bread, which for Christians means preeminently the Eucharistic Bread, and for the purification from sin, so that holy things may be given to the holy.

The priest prays for peace and unity in the Church, greets the people ('The peace of the Lord be with you always'), and invites them to exchange a sign of peace in keeping with local custom. The deacon or priest may give the invitation.

By the Rite of Peace the Church entreats peace and unity for herself and for the whole human family, and the faithful express ecclesial communion and mutual charity before communicating in the Sacrament.

The priest breaks the consecrated Host and places a small piece in the chalice (the commingling), saying quietly, 'May this mingling of the Body and Blood…'. Meanwhile, the Agnus Dei ('Lamb of God…') is sung or said by the people with the choir.

The gesture of the breaking of bread, by which the Eucharist was known in apostolic times, signifies that the many faithful are made one body by receiving Communion from the one Bread of Life. The Agnus Dei accompanies this rite as a plea for mercy.

The priest shows the Host to the people, saying 'Behold the Lamb of God…'. All respond, 'Lord, I am not worthy…'. The priest communicates, then distributes Communion to the faithful, who approach in procession. The Communion Chant is sung during the distribution. After Communion, a period of sacred silence or a hymn of praise may be observed.

Holy Communion is the goal of the Mass: sacramental union with Christ and, through him, with one another. The faithful receive 'that Bread which is Christ himself,' as the fulfillment and purpose of the Sacrifice offered.

After a period of silence or a hymn, the priest stands at the chair or altar and, saying 'Let us pray,' recites the Prayer after Communion. The people respond 'Amen.'

In this prayer the priest petitions for the effects of the mystery just celebrated — that the grace of the Sacrament may bear fruit in the life of the faithful and lead them to eternal salvation.

The priest greets the people ('The Lord be with you… And with your spirit') and blesses them with the sign of the cross ('May almighty God bless you, the Father, and the Son, and the Holy Spirit'). On certain days a Solemn Blessing or a Prayer over the People may be used.

The blessing sends the people forth enriched by the divine life they have received in Word and Sacrament, invoking the protection and grace of God as they depart.

The deacon (or, in his absence, the priest) dismisses the people with one of the approved formulas: 'Go forth, the Mass is ended'; 'Go and announce the Gospel of the Lord'; 'Go in peace, glorifying the Lord by your life'; 'Go in peace.' The people respond, 'Thanks be to God.'

The Dismissal (Ite missa est) gives the Mass its very name: the faithful are 'sent' (missa) to bring forth the fruits of the Eucharist into the world, continuing Christ's mission through their lives.