A slight correction from last time. I read Heidelberg 65, which is important to this series, but I referenced it as Heidelberg 66. I apologize for the confusion.
Heidelberg 65 asks, “where does . . . faith come from?” Great question. Believers want to have faith and a stronger and deeper faith. How do they get that? Heidelberg 65 answers, “From the Holy Spirit who works it in our hearts by the preaching of the gospel and strengthens it by the use of the sacraments.” Aren’t you glad for the gospel of a generous and powerful God? You don’t have to muster up the faith yourself, you simply receive grace from your God, and He builds your faith. You need preaching like you need regular meals if you’re going to have strength on your pilgrim journey to heaven. Additionally, the Holy Spirit strengthens your faith by the use of the sacraments. You need the Lord’s Supper like you need regular meals if you’re going to endure your pilgrim journey to heaven. So then, let’s ask the question: What are the sacraments?
When you hear the word “sacrament” what do you think of? Maybe the word sounds Roman Catholic to you, but it’s not a word reserved for Romanists. The word “sacrament” has been used in the church for a long time. The Protestant Reformers used the word.
According to Webster’s Dictionary 1828, the word “sacrament” comes from the Latin sacramentum meaning an oath, the root being sacer or sacred. Additionally, ancient writers used sacramentum to describe a mystery. But in the history of the church, the word “sacrament” was used to refer to visible signs and seals that communicated the gospel of Christ. Heidelberg 66 defines sacraments as follows:
The sacraments are holy, visible signs and seals. They were instituted by God so that by their use He might the more fully declare and seal to us the promise of the gospel. And this is the promise: that God graciously grants us forgiveness of sins and everlasting life because of the one sacrifice of Christ accomplished on the cross.
So, several things can be said about the sacraments. They are holy, visible, signs, and seals. It’s right to say the sacraments “were instituted by God.” Man didn’t invent the sacraments; God gave the sacraments to man. What does God intend to do through the sacraments? God intends to “more fully declare and seal to [His church] the promise of the gospel.” So the sacraments are declarations and authenticating seals of the gospel of Christ to Christ’s church. The sacraments represent God’s promise to us His church. What’s the promise? The sacraments signify and seal the gospel promise of God to us. Here’s the promise: “that God graciously grants us forgiveness of sins and everlasting life because of the one sacrifice of Christ accomplished on the cross.” It’s really, really important to understand that the sacraments are God’s gift to His church, a gift through which He communicates the gospel and its benefits to them. The sacraments are not gifts that the church gives to God. The sacraments are not a response to the gospel per se, they are the gospel being given by God to His church as they obediently receive them. To make the sacraments something that the church gives to God in response to the gospel or does in order to say something about themselves is to change the primary intent of the sacraments. The sacraments signify and seal the gospel; they communicate what God has done for us and not what we do for God. That’s all-important.
Here’s how the Westminster Confession of Faith defines the sacraments. Chapter 27:1 says:
Sacraments are holy signs and seals of the covenant of grace, directly instituted by God, to represent Christ and his benefits; and to confirm our interest in Him: as also, to put a visible difference between those that belong to the Church and the rest of the world; and solemnly to engage them to the service of God in Christ, according to His Word. 
That’s very similar to Heidelberg 66, but let me draw your attention to several things. First, sacraments are “holy signs and seals of the covenant of grace.” The covenant of grace is the gospel in which God offers sinners salvation and life in Christ. The covenant requirement is faith in Christ apart from whom there is no reception of the benefits of the gospel. But God promised to grant His people true faith, which is comforting (WCF 7:3). Second, the sacraments were “directly instituted by God.” They are God’s gifts to His church. Third, God instituted His sacraments “to represent Christ and his benefits.” That’s big. The sacraments represent the gospel. They represent what God has done for His people in and through Christ His Son. Fifth, the sacraments are given to the church to “confirm our interest in [Christ]” or to make firm our faith, to comfort us in the gospel, to strengthen our confidence in Christ. God uses the sacraments to strengthen His covenant people. Sixth, and please understand this significant point, the sacraments place a visible difference between those who belong to Christ in the visible church and the rest of the world. A person who does not receive the sacraments does not receive that which demarcates them from the world, which communicates they are of the world and not of Christ and his church.
Westminster Shorter Catechism 92 defines a sacrament like this: “A sacrament is a holy ordinance instituted by Christ, in which, by perceptible signs, Christ and the benefits of the new covenant are represented, sealed, and applied to believers.”  You heard the word “ordinance” there. That simply means an “established rite or ceremony.”  The sacraments are ceremonies given to the church by Christ. And they are not empty ceremonies. They are full of meaning, purpose, and grace. Through the sacraments, Christ represents, seals, and applies to believers—so you need to be united to Christ by faith to receive what the sacraments signify and seal—Christ represents, seals, and applies to believers the benefits of the new covenant or the benefits of the promise of the gospel.
Westminster Larger Catechism 162 adds a bit more detail. It defines a sacrament like this:
A sacrament is an holy ordinance instituted by Christ in His Church, to signify, seal, and exhibit to those that are within the Covenant of Grace, the benefits of His mediation; to strengthen and increase their faith and all other graces; to oblige them to obedience; to testify and cherish their love and communion one with another, and to distinguish them from those who are outside the Covenant of Grace. 
That says a lot but notice one thing. Sacraments are for those “within the covenant of grace.” The sacraments are for those whom God graciously puts into the covenant of grace, for those whom God makes promises. To whom does God make gospel promises? Check out Acts 2:39! Also notice that Christ gives the sacraments to his church “to strengthen and increase their faith.” That’s really important.
Fellow believers, Christ gives you the sacraments to comfort your soul, to assure you of the gospel, and to work in you a stronger more robust faith. Christ loves and serves you in and through the sacraments. Receive the sacraments and believe the gospel, for that is why God gives the sacraments to you. They declare to you the gospel, and you receive all the benefits of the gospel when you trust Christ and receive the sacraments by faith.
Maybe next time I can get into Article 33 of the Belgic Confession. It’s excellent. I recommend you meditate on it. It is packed full of helpful clarifications that will encourage you to treasure the sacraments more deeply.
This all relates to the Lord’s Supper because the Lord’s Supper is a sacrament. The Lord’s Supper is a divine gift meant to declare and seal to us, Christ’s church, His great promise of the gospel of a crucified and risen Christ. Receive the sacraments with gratitude, and rejoice in the gospel given you in and through them.
 The Confessions of Our Faith, Fortress Edition, ed. Rev. Brian W. Kinney (Fortress Book Service & Publishers, 2007), 48.
 Ibid., 138.
 The Confessions of Our Faith, 108.
Quotes from the Heidelberg Catechism are taken from Zacharias Ursinus & Jonathan Shirk, The Heidelberg Catechism (Manheim: Small Town Theologian, 2021).
Scripture quotations are from the ESV® Bible (The Holy Bible, English Standard Version®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved. May not copy or download more than 500 consecutive verses of the ESV Bible or more than one half of any book of the ESV Bible.