The ends and uses of this sacrament are various.

1. It was instituted to be a memorial of the death of Christ. That it is a commemorative ordinance, appears from the Saviour’s words: “This do in remembrance of me;” and that it is especially a memorial of his death, is evident from his words in distributing the elements. While he gave the bread to his disciples, he said: “This is my body, which is broken for you;” and of the cup he said: “This cup is the New Testament in my blood.” The ordinance is eminently fitted to bring to our remembrance the reality and the painful nature of the death of Christ—to remind us of the vicarious nature of his death, of its acceptableness to God as a satisfaction for our sins, and of its present and perpetual efficacy. And we should remember his death with a lively and appropriating faith; with ardent love to him who first loved us; with deep contrition for our sins, the procuring cause of his death; with holy joy in God; and with the warmest gratitude to Christ, who gave himself for us an offering and a sacrifice to God for a sweet-smelling savour.

2. This sacrament seals the benefits of Christ’s death unto true believers. It seals not the truth of christ’s death, nor the truth of their faith; but it seals the right and interest of faith, as the seal affixed to a deed seals the right and interest of the person in the property conveyed by that deed.

3. It promotes the spiritual nourishment and growth of believers. A devout participation of this ordinance is fitted to confirm and invigorate their faith, to inflame their love, to deepen their godly sorrow, to enliven their joy, and to enlarge and strengthen their hopes of the Saviour’s second coming, and of the glory then to be revealed.

4. It is a sign and pledge of the believers’ communion with Christ. This is evident from the words of Paul (1 Cor. 10:16): “The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ?” These words certainly import that, in the holy supper, believers have communion with Christ in the fruits of his sufferings and death.

5. It is an emblem of the saints’ communion with each other. All true saints are members of one body, and in the holy supper they have communion, not merely with those who sit along with them at the same table, but “with all that in every place call on the name of Jesus Christ,” their common Lord. “We being many,” says Paul, “are one bread, and one body; for we are all partakers of that one bread.”—1 Cor. 10:17. This ordinance is very expressive of the communion of saints, and has a powerful tendency to cherish it. They meet together at the same table, as brethren and children of the same family, to partake of the same spiritual feast.

6. In this ordinance believers engage themselves to all the duties which they owe to Christ. They acknowledge him as their master, and engage to do whatsoever he has commanded them. Persons may come under engagements by performing certain significant actions, as well as by express words. Submission to the ordinance of circumcision, under the former dispensation, made a man “a debtor to do the whole law.” Baptism, in like manner, under the Christian dispensation, involves an engagement to be the Lord’s; and Christians, in partaking of the Lord’s supper, renew this engagement. They acknowledge that they are not their own, but are bought with a price, and bind themselves to glorify God with their bodies and spirits which are his.

—An Exposition of the Westminster Confession of Faith by Robert Shaw