The Reformed tradition views the Lord's Supper as a sacrament of the New Testament where believers, by faith and the work of the Holy Spirit, truly and really feed upon the body and blood of Christ for their spiritual nourishment and growth in grace, while denying any corporal or carnal presence of Christ within the elements.
In the Reformed tradition, the Lord's Supper is more than a mere memorial of Christ's death; it is a means of grace. While Reformed theology explicitly rejects the Roman Catholic doctrine of transubstantiation and the Lutheran view of a physical presence, it firmly maintains that Christ is truly and really present to the believer. This presence is not found in the bread and wine in a carnal or corporal manner, but is experienced through the power of the Holy Spirit as the believer feeds on Christ by faith. As expressed in the Westminster Larger Catechism — Question 170, communicants feed upon Christ's body and blood not with their mouths, but through the application of the benefits of Christ crucified to their souls, resulting in spiritual nourishment and union with their Savior.
The Supper serves as a sacred pledge of God's continued liberality and our union with Christ. The Heidelberg Catechism — Question 81 clarifies that this table is instituted for those who are truly sorrowful for their sins and trust that these are forgiven for the sake of Christ. It is a time for the strengthening of faith and an engagement to live more holy lives. This necessitates a posture of self-examination as commanded by the Apostle: "But let a man prove himself, and so let him eat of the bread, and drink of the cup" (1 Corinthians 11:28). We approach not as those who have attained perfection, but as beggars coming to the true Bread of Life who alone sustains our spiritual existence.