In my experience, many Christians struggle to understand what they believe and to find the right words to communicate what they believe. This is where creeds, confessions, and catechisms help Christians immensely. They define and explain things in simple terms—terms children can learn and understand—and unite Christians around a common understanding of Scripture. Creeds, confessions, and catechisms communicate, “This is what we believe as Christians, and this is what we do not believe.” That’s a very helpful thing to have. We can’t simply know what we believe, we must also know what we do not believe. That’s called discernment.
Sometimes, professing Christians will confess things found in Scripture only to understand those doctrines in an erroneous way. For example, they might believe Jesus died on the cross for them, but they might understand that to mean Jesus will heal them of all sicknesses in this life and that the cross is actually not about their sin but about their inherent value. Creeds, confessions, and catechisms guard us against falling prey to soul-destroying lies like this.
So, what’s the Lord’s Supper all about? Test yourself. What do you believe? What don’t you believe? Is the Lord’s Supper Law or Gospel? In other words, is the Lord’s Supper primarily something you must do in response to the gospel or is it primarily something that Christ is doing for you? Are you doing for Christ in the Lord’s Supper or is Christ doing for you? Where’s your emphasis? These are important questions.
As Christians, we have a way of putting ourselves at the center of the Bible. We’re constantly tempted to put ourselves where Christ should be. For example, in his battle against Goliath, Christians often see themselves as David. They miss that David is a type of Christ. David defeats Goliath like Christ defeats sin, death, and the devil. Another example is Jonah. Christians interpret Jonah as, “Don’t be like Jonah who ran from God; run to God and obey Him; God has a plan for my life” and they miss that Jonah is about Jesus’ death and resurrection (Matt. 12:40). They put themselves where Jesus should be.
Might we do this with baptism and the Lord’s Supper? Might we mistakenly make the sacraments about ourselves, about something we do, and not about the grace that Christ extends us? Is that why God gave us baptism and the Lord’s Supper, so that we can think about ourselves? This ultimately undermines our assurance and comfort in the gospel because we’ve turned the Gospel into Law.
I commend to you Article 35 of the Belgic Confession. A link is in the show notes. Read over Article 35. Try to understand it. The purpose of Article 35 is to help you understand how the Lord’s Supper is grace for you, how Jesus is serving you in the Lord’s Supper. If you understand the Lord’s Supper to be something you are doing for Christ, you do not understand the Lord’s Supper; Christ is doing something for you.
You are not only alive physically; you are also alive spiritually. You were made alive in your second birth (Jn. 3). You came alive when the Holy Spirit worked faith in your heart by the hearing of the gospel. God made you alive in Christ (Eph. 2:5; Col. 2:13). My question to you is this. As is the case with your physical body, does your soul need to eat and drink in order to be strong and healthy?
Article 35 compares our physical and earthly life with our spiritual and heavenly life. It explains that not only do we need to eat and drink to be strong and healthy physically, but we also need to eat and drink to be strong and healthy spiritually. Isn’t this what Christ wants to communicate to us through the Supper? Article 35 says:
But to maintain the spiritual and heavenly life that belongs to believers he has sent a living bread that came down from heaven: namely Jesus Christ, who nourishes and maintains the spiritual life of believers when eaten—that is, when appropriated and received spiritually by faith. 
Please consider this carefully. Why would Jesus say, “I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst” (Jn. 6:35). Doesn’t Jesus mean that he can satisfy the hunger and thirst of your soul? Jesus seems to mean that through faith, he will satisfy your soul. How does he do that? What should we believe to receive Jesus? The gospel is given to you in the Word and sacraments, correct?
Why would Jesus say, “I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing” (Jn. 15:5). Why did Jesus talk like that? Wasn’t he saying that, as the vine, he nourishes, strengthens, and sustains the branches upon whom he grows fruit? He gives life to the branches, correct? How exactly does he do that? The branches are already connected to him; they are abiding in him; he is abiding in them; so how does Jesus give life to those united to him? He gives them life through faith, correct? And how does he continue to sustain and nourish their faith? Through his Word and sacraments, correct?
The Belgic says that Christ “nourishes and maintains the spiritual life of believers when eaten—that is, when appropriated and received spiritually by faith.”  Do you believe that Jesus nourishes and maintains your spiritual life? If so, how do you expect him to do it? Do you believe the Word is the only means of grace he uses to build up your faith? I hope not, because the sacraments are the Word of the gospel made visible to you. They too strengthen your faith. Christ extends the promises and benefits of the gospel to you in the Lord’s Supper, and when you appropriate them, meaning you take the Supper into yourself for your own use and benefit, when you receive Christ into yourself by faith, Christ is bread for your soul, drink for your soul; Jesus is the nourishment you need to live for God. Christ gave you the gift of the Lord’s Supper, not so much to ask you to do another thing, as if it’s law, though we do need to obey him and observe the Lord’s Supper. Christ gave you the Lord’s Supper as a gift to bless you, as a gift through which he gives you himself and you receive assurance and comfort for your soul. The sacraments are Gospel, not Law. Christ serves you in the Supper. Why? He loves you.
Article 35 continues:
To represent to us this spiritual and heavenly bread Christ has instituted an earthly and visible bread as the sacrament of his body and wine as the sacrament of his blood. He did this to testify to us that just as truly as we take and hold the sacraments in our hands and eat and drink it in our mouths, by which our life is then sustained, so truly we receive into our souls, for our spiritual life, the true body and true blood of Christ, our only Savior. We receive these by faith, which is the hand and mouth of our souls. 
Christ doesn’t simply tell us the gospel. He shows us the gospel. He gives us something visible to see, touch, smell, and taste; he gives us something to experience to strengthen our confidence in the gospel. When we receive the elements of bread and wine into our hands, and when we taste them with our mouths, we experience something physical. This physical experience reminds us of a spiritual experience that’s happening synonymously—Christ is nourishing and strengthening our souls with himself, with all of himself, with his crucified body and shed blood. As we believe the gospel that the Lord’s Supper signifies and seals for us, we are receiving and enjoying the forgiveness of sins, life in Christ, communion with Christ, communion with one another, the love of God, spiritual nourishment and refreshment, etc. If Christ doesn’t give us something tangible to experience, we’d be less likely to believe that Christ is actually giving and sustaining life in us. We can’t see that happening. We can experience bread and wine, and that’s why he gives us bread and wine. They help us believe the gospel. Christ is actually feeding and sustaining us with himself, and that’s what the Supper is all about.
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.