"And he received the sign of circumcision, a seal of the righteousness of the faith which he had while still uncircumcised" (Rom. 4:11a).
During the next six studies we will look at the means of grace God uses to bring unity to His people and glory to Himself: the sacraments. The word is not a biblical term but designates ordinances instituted by God as a sign and seal of grace. We find two in the New Testament—the Lord’s Supper and Baptism. Louis Berkhof defines a sacrament as “a holy ordinance instituted by Christ, in which by sensible signs the grace of God in Christ, and the benefits of the covenant of grace, are represented, sealed, and applied to believers, and these, in turn, give expression to their faith and allegiance to God.”
A sacrament must be instituted directly by Christ Himself. Christ instituted baptism on the eve of His ascension (as it is distinguished from the baptism of John, which was transitional and preparatory). He instituted the Lord’s Supper on the night of His betrayal when He celebrated the Passover with His disciples one last time.
A sacrament is a visible sign of invisible grace. The sacrament signifies more than just a general truth, but a promise given to God’s people. This serves to strengthen our faith as we consider the realization of the promise. The visible sign, or material element, in a baptism is water, representing purification or cleansing. The material elements in the Lord’s Supper include bread and wine, which represent union with Christ in His death and resurrection. The meaning of the sacraments should be brought to the people through the preached word, that they might properly worship God in these ordinances.
The sacraments of baptism and the Lord’s Supper serve to confirm to God’s people the grace that they signify—purification in baptism and the atonement in the Lord’s Supper. God’s people are called continually to observe these sacraments.
When you consider these requirements for a sacrament—instituted by Christ Himself, visible forms of invisible grace, a confirmation of the grace they signify, and the command to observe them perpetually—only baptism and the Lord’s Supper meet the criteria. When the church faithfully administers these sacraments, it receives blessings from God as it is strengthened by the grace they signify.