Sermon -- Holy Trinity (May 31, 2026)

THE HOLY TRINITY IS AN ETERNAL MYSTERY.

MATTHEW 28:16-20

In the name + of Jesus.

     The Bible contains a number of hard teachings.  When people encounter them, they tend to want to make the hard teachings easier.  They rework the Biblical account to make it appealing to human reason.  So, for example, our Old Testament reading detailed the creation of the universe.  God created the heavens, the earth, and everything in them in six 24-hour days.  You will not find that in any science text book.  So, how do you uphold the Bible and still say that you trust the science?

     The solution for many Christians is to interpret the first chapters of the Bible as a parable.  But here is the problem: Genesis is a historical account, and it is to be read as a historical account.  When Jesus told parables, he made it clear that it was a parable.  Many of Jesus’ parables begin, “The kingdom of God is like” and so forth.  It is clear that Jesus is making a comparison, and that is how we understand it.  We find no such literary device regarding the creation. 

     It is only when people do not believe God’s word that they argue it is to be understood as a parable.  They trust the science, but they do not trust the word of the Lord.  They read that God created the heavens and the earth in six days, but they follow up by insisting, “Well, that’s not what it means.”  That is unbelief.

     This evolutionary mindset continues with doctrine as well.  Many theologians argue that Christian doctrine developed over time.  They will say that the resurrection of the body was a later addition to the faith.  They will also claim that the doctrine of the Trinity was a later innovation.  For example, some contest, “Did Noah or Abraham think the Lord is a Triune God?  Look at the Bible and you will see they never said ‘Father, Son, and Holy Spirit’!”  That sounds persuasive.  But just because they did not use the phrase, “Father, Son, and Holy Spirit” does not mean they did not confess the Lord rightly. 

     Jesus gave us the most vivid revelation of God.  He regularly referred to God as his Father.  He also made it clear that he is the Son.  Jesus declared, “All should honor the Son just as they honor the Father.  Whoever does not honor the Son does not honor the Father who sent him” (John 5:23).  If they are to share equal honor, then they are equally God—Father and Son.  Jesus also told his disciples, “When he, the Spirit of truth, comes, he will guide you into all truth” (John 16:13).  If the Holy Spirit is the source of truth, then he, too, is God.  That is why Jesus told us to baptize “in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19).  It is not in the names, as if there are three gods.  It is in the name, because God is one, just as Scripture says: “Hear, O Israel!  The LORD is our God.  The LORD is one” (Deuteronomy 6:4)!  And yet this one God is Father, Son, and Holy Spirit.

     This is a hard teaching.  In fact, it is an eternal mystery.  It did not develop over time.  God is unchanging.  Even if the revelation of God became clearer over time, God did not change who he is.  The Holy Trinity is an eternal mystery.  It is not a secret, however.  It cannot be a secret because you know what it is.  You know that God is one, just as we confess in the Nicene Creed: “We believe in one God.”  And God is three persons—Father, Son, and Holy Spirit.  That is no secret.  God tells us that plainly about himself.  We, however, cannot understand it.  That is what makes it a mystery.  Every effort to logically explain this mystery ends up destroying the teaching—either resulting in three gods or melding the three persons into one.  Rather than try to make a hard teaching easier by changing it, we marvel at it. 

     The Holy Trinity is an eternal mystery.  But the world did not have to wait for the coming of Jesus to reveal it.  Since the Lord is eternal and unchanging, we find the same God on page 1 of our Bibles as we do in Jesus’ command to baptize.  This is what we hear at the foundation of the world: “In the beginning, God created the heavens and the earth.  The earth was undeveloped and empty.  Darkness covered the surface of the deep, and the Spirit of God was hovering over the surface of the waters.  God said, ‘Let there be light,’ and there was light” (Genesis 1:1-3).  First, there is the mention of God the Father almighty, maker of heaven and earth.  Then there is the Holy Spirit, hovering over the waters.  He is the Lord and giver of life, since the Holy Spirit plus water equals a new creation, just as he did in your baptism.  So, where is God the Son?  The Apostle John calls him the Word.  “In the beginning was the Word.  …Through him everything was made, and without him not one thing was made that has been made” (John 1:1,3).  So, when God the Father spoke, the Son was at work.  The Holy Trinity was there—as it was in the beginning, is now, and ever shall be, world without end.  Amen.

     The Holy Trinity is an eternal mystery.  Something else which is a mystery is how people who are without sin and in harmony with God’s will can rebel and choose what is evil.  That happened with Adam and Eve.  Satan had convinced them that taking what God had forbidden would produce happiness and freedom for them.  He sold it this way: “God knows that the day you eat from (the forbidden tree), your eyes will be opened, and you will be like God” (Genesis 3:5). 

     To this day, this desire to be like God is the root of all sin.  We want our own way.  When God presents us with a hard teaching, we conclude that God is the one with the problem or that he did not really mean it.  We reject God’s word when it corrects or condemns us.  We pray, telling God to bend his will to our will.  When God tells us “No,” we look for someone who will tell us, “Yes!  Go and do it!  You’ll be happy you did!” 

     Not only is God’s word rejected, God himself gets re-created.  People have always crafted gods who are just like they are.  Canaanite gods promoted sexual promiscuity.  Guess why they were popular.  Going to the altars of Roman gods promised prosperity.  Guess why they were popular.  And anyone who is spiritual crafts a god who is just like he is.  Who wouldn’t love a god who agrees with you on everything?

     But a god who has to be created is a powerless god.  A god who you can disagree with and who will not uphold his own commands is a useless god.  That is why Adam and Eve did not take their stand against the Lord and say, “Look now, we are gods, too!  Respect us!”  Instead they hid in fear from the Lord, knowing that they deserved the death God had threatened.  If you do not recognize your own sin, you might look brave as you boast about your importance.  But in the end, death comes to all.  All will be judged by God because he is God and we are not.  No sinner will stand before him.  Repent.

     The Triune God is unchanging.  Mankind had changed because of sin, but God is still merciful, slow to anger, and abounding in love and faithfulness.  So, the Triune God promised to save sinners—from the very first sinners.  He promised to destroy the devil’s work.  That means he promised to take away the curse of sin.  The Lord had warned what sin meant: “You shall surely die” (Genesis 2:17).  But he promised to reverse death.  God’s work of salvation means, “You shall surely be delivered from death and live!”  So, you see, even the resurrection of the dead is not a doctrine that developed over time.  Our sin infected bodies will die, but the Lord himself assumed a body in order to rescue us completely from the effects of sin. 

     The eternal God entered our time as a mortal man.  This, too, is a great mystery that God became a man and yet remain unchanged.  We will confess that later in the Athanasian Creed, although we still will not be able to wrap our heads around it.  It remains an eternal mystery.  Just because it is a hard teaching does not make it untrue.  God became a flesh-and-blood man so that he could live in our place, perfectly obedient to God’s word.  He did not seize the world by force or consider equality with God as a thing to be grasped.  Rather, the Son of God lived in humility, perfectly dependent upon the goodness of his Father. 

     More than that, the Son of God willingly took from his Father the cup of wrath that was meant for the people of the world.  After all, we had earned it.  But out of love for mankind, the Father sent his Son to consume all divine wrath for us.  The Son willingly took the cup—first, out of love for his Father and then, out of love for mankind.  God the Son was slain on behalf of people who longed to be gods themselves.  Then he took up his life again to secure our own resurrection from the dead—a resurrection to life and light and glory and peace.  And to grant us the right to become children of God, Jesus sent the Holy Spirit to convert us from rebels to righteousness. 

     This is why Jesus tells us to baptize people “in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19).  The Holy Trinity made you his very own through baptism.  He cleansed you of all sin and set you apart for a godly life both now and in eternity.  While we glorify God the Son for our saving work, the Holy Trinity fully invested himself in saving and restoring what was ruined by sin.  God the Father sent his only begotten Son to save us.  God the Son became a man to unite himself to us.  He consumed all of God’s wrath so that we are not consumed by it.  He rose from the dead to eliminate death.  He exalts our humanity so that we will be restored to the perfection God had intended.  He will restore the Paradise he had created.  God the Holy Spirit works in us to believe even the hard teachings, to teach us “to keep all the instructions [the Lord has given]” (Matthew 28:19), and “to will and to work, for the sake of his good pleasure” (Philippians 2:13).

     The Holy Trinity is an eternal mystery.  It is a hard teaching; but just as I cannot tell you what you are like, so also God must tell us what he is like.  He reveals himself as one God who is Father, Son, and Holy Spirit.  You and I will never be able to unravel this mystery.  In fact, I wonder, will the Holy Trinity remain a mystery even when we see him in the glories of heaven?  I don’t know.  But rather than try to unravel the mystery, we will simply marvel at it. 

     Our greatest comfort comes not from what we cannot understand, but from what we do: The Holy Trinity is on our side and serves for our good.  He is the God who saves, who loves his children, and who longs for us to dwell with him forever. 

     “May the God of peace himself sanctify you completely, and may your whole spirit, soul, and body be kept blameless at the coming of our Lord Jesus Christ.  The one who calls you is faithful, and he will do it” (1 Thessalonians 5:23-24).

In the name of the Father and of the Son + and of the Holy Spirit.  Amen.