In pondering the meaning of the Lord’s Supper, there is a long tradition of using biblical signs to understand the Christian sacraments, such as the sign of the rainbow given to Noah, the sign of circumcision given to Abraham, and the sign of Passover given to Moses. So many of the prophets had given signs to seal the promises they had been sent to proclaim. It is in terms of these signs of God’s prior covenant dealings that we can understand the sacrament of the Lord’s Supper. The 19th century American Presbyterian minister Samuel Davies expresses this very simply and clearly:
Every sacramental institution seems to partake of the general nature of a seal, that is, it is a sensible sign for the confirmation of a covenant or contract. Hughes Oliphant Old, Holy Communion in the Piety of the Reformed Church, p. 658
Although Scripture is expressly clear that we are justified by grace through faith, yet the sacraments do have a very significant role in our redemption; the sacraments become signs and seals of the salvation that comes by faith. The sacraments do not save us; rather, we are saved by the grace of God working through faith. The sacraments are a sign of that grace and a seal of the promise of salvation through faith. In applying this to the Lord’s Supper, we may consider this ordinance as a seal of the covenant of grace, both upon God’s part and upon ours. When we consider the words of institution in 1 Corinthians 11:25, it means that to drink of the cup is to receive the sign and seal of the New Covenant.
To understand this point more fully, it’s necessary to note that God deals with the human race through covenants. In the New Covenant, God is one party to this covenant, man is the other, and Christ is the mediator. The terms of the covenant are that out of His love for us, He is willing to restore sinners to the life for which God had originally created us. In view of the atoning sacrifice of His Son, He is willing to bestow pardon for all our sin, the blessings of this life, and the gift of eternal life upon all those who truly desire to know God and serve Him according to His Word. For our part, we are to receive Jesus Christ as our Lord and Savior. We are to believe in Him with all our hearts, repent of our sin, and devote ourselves to Christ’s service. This is the essence and substance of the New Covenant: and of this the Lord‘s Supper is a seal as to both parties.
This raises a question: does the covenant really need to have a sign or a seal for it to be valid? Is it not enough for the covenant to be proclaimed and for us to receive it by faith? To this question, Samuel Davies answers:
On God’s Part this covenant can receive no intrinsic confirmation. He has plainly declared it in His Word; and no oaths or confirming signs can add any intrinsic certainty to His declaration. Hughes Oliphant Old, Holy Communion in the Piety of the Reformed Church, p. 659
It is often said that an honest man’s word is as good as his bond. How much more is it true of the Word of God? God’s Word needs no external authority or proof. It is its own authority, simply because it is God’s Word. Yet from the human standpoint a sign is necessary because of the weakness of human flesh. It is for the sake of our human weakness that God regularly confirms His Word with signs and wonders and thus, human weakness makes signs necessary. So it is from the human side of things that sacraments are signs and seals which make clear our participation in the covenant.
As we receive the Lord’s Supper, may we be reminded of God’s great love for us in Christ and in His condescension to give us visible signs of His covenant. As we receive the Lord’s Supper, may we consider the words of Samuel Davies.
As our part in receiving these elements, we signify our hearty consent to the covenant of grace, and, as it were set out seal to it to confirm it. The language of that speaking action is to this purpose; ‘I cordially agree to the plan of salvation through Jesus Christ revealed in the gospel; and in token thereof I hereunto affix my seal. As I take his bread and wine before many witnesses, so I openly and avowedly take and receive the Lord’s Jesus as my only Savior and Lord.’