The Liturgy is the everlasting interaction of the gathered community being united in the body of Christ. The liturgy can be understood as an ontological interaction with Christ as the community is constantly being molded in the image and likeness of Christ (cf. Gen 1.26-27). That is why a presbyter can never celebrate a liturgy without the gathering of the community because the community represents the living body of Christ in the world. The presbyter recites during the institution narrative "for He gave his life up for the world". The He, being Christ, is what is being offered on behalf of all and for all. If Christ is being offered for all and we represent His image and likeness then we to are also asked to give up our lives for the life of this world. When we gathered together to celebrate the liturgy it is a joyful occasion because after the death of Christ we live in the joy of the resurrection. It was through death that we received life. The following are passages taken from Archimandrite Robert Taft, who is the world's leading figure on liturgy. The passages sum up what the liturgy should represent and not what we make liturgy ought to be.
Our true Christian liturgy, therefore, is just the life of Christ in us that we both live and celebrate. That life is none other than what we call the Holy Spirit. This is salvation, our final goal. The only difference between this and what we hope to enjoy at the final fulfillment is that the mirror spoken of in 1 Cor 13:12 will no longer be needed: as Adrien Nocent put it, the veil shall be removed." + Archimandrite Fr. Robert Taft
This gives liturgical prayer a concentration on the essential rather than the peripheral; it gives our prayer equilibrium insofar as its rhythms are set by the Church and not by our own private subjectivity and sentiment. How much penance, how much contrition, how much praise, how much petition, how much thanksgiving should our prayer-life contain? It is all right there in the pedagogy of the Church's liturgy. How much devotion to the Holy Trinity, how much attention to the Mysteries of Christ's life, how much to his Passion, how much to the Mother of God, how much to the saints? How much fasting, how much feasting? Our liturgical calendar with its seasonal and festive rhythms has it all. This gives a balanced and objective comprehensiveness to the Church's prayer that is a sure remedy for the one-sided excesses and exaggerations of a subjective devotionalism that emphasizes only those aspects of prayer that have personal appeal to some particular culture or individual at any given moment, often for less than ideal reasons." + Archimandrite Fr. Robert Taft