86 This has already been stated in the clearest terms by some of Our predecessors and some Doctors of the Church. "Not only," says Innocent III of immortal memory, "do the priests offer the sacrifice, but also all the faithful: for what the priest does personally by virtue of his ministry, the faithful do collectively by virtue of their intention." We are happy to recall one of St. Robert Bellarmine's many statements on this subject. "The sacrifice," he says "is principally offered in the person of Christ. Thus the oblation that follows the consecration is a sort of attestation that the whole Church consents in the oblation made by Christ, and offers it along with Him."
Source: Mediator Dei (Vatican.va)