103 Let this, then, be the intention and aspiration of the faithful, when they offer up the divine Victim in the Mass. For if, as St. Augustine writes, our mystery is enacted on the Lord's table, that is Christ our Lord Himself, who is the Head and symbol of that union through which we are the body of Christ and members of His Body; if St. Robert Bellarmine teaches, according to the mind of the Doctor of Hippo, that in the sacrifice of the altar there is signified the general sacrifice by which the whole Mystical Body of Christ, that is, all the city of redeemed, is offered up to God through Christ, the High Priest: nothing can be conceived more just or fitting than that all of us in union with our Head, who suffered for our sake, should also sacrifice ourselves to the eternal Father. For in the sacrament of the altar, as the same St. Augustine has it, the Church is made to see that in what she offers she herself is offered.
Source: Mediator Dei (Vatican.va)