As Robert Sokolowski explains in his book, Eucharistic Presence: A Study in the Theology of Disclosure, in the Eucharist past and future are made present. That is, past events of salvation history such as the Jewish Passover, but especially the Christ-event and future eschatological realities are brought together. Sokolowski then offers a beautiful reflection on our union with Christ in death.
[W]e in the Eucharist anticipate our own death as to be joined to the death of Jesus. Our death becomes part of the divine mystery, part of the great saving actions of God, because it can be identified with the sacrificial death of Christ. [...] The celebrations of the Eucharist at which we assist are like so many rehearsals of the one transition, the one exodus that is reserved for each of us, the one offering in which we no longer sacramentally but bodily participate in the death of the Lord. As Jesus acted toward the Father in his death, so we are enabled to make our death an act before God, an act in which life is changed, not taken away. [...] Our death, which is the horizon marking off the edge of our life, becomes a particular image of the final restoration of all things in Christ, an image of the death of things that is now to be understood as a transition into the kingdom of God. The Eucharist thus presents a double future to each of us as we participate in it: it presents our own entrance into the death and Resurrection of Jesus, and it presents the more remote setting in which everything will be restored in the kingdom of God.
These enactments of past are future are all woven into the Eucharist we celebrate in the present. The celebration of the Eucharist is surrounded by temporal ripples through which past and future things are refracted. The Eucharist does not give us merely images or signs of what is past and future; it presents these things as past and as future to us now. The Eucharist involves memory and anticipation, but it does not involve them as mere psychological states; rather, it reenacts and preenacts things God has done and will do (104-5).
Sokolowski, a few pages later, says that the Eucharist is from one perspective something that takes place in time. That is, it takes time to celebrate it; yet, “it also overcomes time as it reenacts an event that took place at another time. In doing this, the Eucharist calls time into question. It claims to go beyond time and thereby indicates that time and its succession are not ultimate. It makes time to be an image; it makes succession to be a representation. Thus the Eucharist, in its reenactment of the past and anticipation of the future, also enacts for us the context that encloses past, future, and present: it enacts the eternal life of the God who could be all that he is, in undiminished goodness and greatness, even if the world and its time were not [!]. The Eucharist engages, and perpetually reminds us of, the Christian distinction between the world and God” (107).