If there is a “meet and greet”
during the Mass, that is illicit. There is no such thing. My parish does a “turn and greet your neighbor” before the opening hymn is sung. (We also have the Sign of Peace.)
The Sign of Peace itself (among the faithful)
is optional; it is up to the priest or deacon to decide whether to include it in the Mass. But the Sign of Peace is
not a “meet and greet”.
The priest then offers us the peace of the Lord, and we reply “And with your spirit.” Then he or the deacon
may invite us to offer one another that peace. While the Roman Missal does not define the words to say to one another, these words (which are those of the priest, too) are suggested:
Pax Dómini sit semper vobíscum.
The peace of the Lord be with you always. Gal. 1:3; Phil. 4:7; 2 John 1:3
to which we should respond “Amen.” Common variants of this greeting are “Peace be with you” and “Peace of Christ be with you.”
St. Paul wrote eloquently to the Philippians about how God and peace are inseparable:
Have no anxiety about anything, but in everything by prayer and supplication with thanksgiving let your requests be made known to God. And the peace of God, which passes all understanding, will keep your hearts and your minds in Christ Jesus. Finally, brethren, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is gracious, if there is any excellence, if there is anything worthy of praise, think about these things. What you have learned and received and heard and seen in me, do; and the God of peace will be with you. (Phil. 4:6-9)
The peace of God comes to us when we let go of worry and anxiety, and prayerfully place our trust in God. God, Who is the source of peace, comes to us when we focus our minds on the virtuous example of Jesus and the saints and imitate them.
It is important to be reconciled not only to God but to one another before we receive Communion. St. Augustine explained why:
Christ the Lord … consecrated the sacrament of our peace and unity upon his table. Who accepts the sacrament of unity, and keeps not the bond of peace, does not receive the sacrament for his good, but as a testimony against himself!
While different Rites of the Church place the Sign of Peace in different places, it is important to recognize the necessity of being at peace when offering sacrifice to the Lord:
“So if you are offering your gift at the altar, and there remember that your brother has something against you, leave your gift there before the altar and go; first be reconciled to your brother, and then come and offer your gift.” (Matt. 5:23-24)
The Sign of Peace is not intended to be a “break” in the Liturgy of the Eucharist, a liturgical pause between the Our Father and the Lamb of God. Nor is it supposed to be a social interlude for catching up with old friends. This part of the Mass is a manifestation of the communion we share with Christ and with all those who belong to him. It is a liturgical action meant to express “peace, communion, and charity” (GIRM 154) to one another. While a hug or kiss may be appropriate between close relations, this is not a time to make people uncomfortable by “invading their personal space.” It is appropriate to “offer the sign of peace only to those who are nearest and in a sober manner.” (GIRM 82)