Trinity Sunday—The Doctrine of the Trinity in the Old Testament
In the Name of the Father and of the + Son and of the Holy Spirit. Amen.
“Peter, an apostle of Jesus Christ, to the pilgrims of the dispersion in Pontus, Galatia, Cappadocia, Asia, and Bithynia, elect according to the foreknowledge of God the Father, in sanctification of the Spirit, for obedience and sprinkling of the blood of Jesus Christ. Grace to you and peace be multiplied” (1 Peter 1:1-2).
These are the words of Saint Peter in his first letter to the church. These words speak the same truths we heard Jesus speak of in John chapter 3 this morning. When our Lord Jesus says, “For God so loved the world that He gave His only begotten Son that whoever believes in Him should not perish but have eternal life” (John 3:16), He is speaking of that same triune God that Saint Peter speaks of in his greeting to the church.
God the Father who chose us, elected us, and foreknew us before the foundation of the world to be saved for the sake of His Son. God the Son who sprinkled His blood, poured it out on the cross, and presented it to the Father for our sins. God the Spirit, God the Spirit who sanctifies us, that is by the merits of Jesus’ blood, delivered to us through Word, Baptism, Absolution, and the Lord’s Supper. This God the Holy Spirit sanctifies us, sets us apart. The Spirit takes us out of the kingdom of the devil, an unbelieving world, and places us firmly in God’s kingdom, the kingdom of grace, the kingdom of the triune God.
As Luther puts it in the Large Catechism, “Christ has acquired and gained the treasure for us by His suffering, death, resurrection, and so on, like Peter says, obedience and sprinkling of blood of Jesus Christ. But if the work remained concealed, the work that the Father sent Jesus the Son to accomplish, if it remained concealed so that no one knew about it, then it would be useless and lost. So that this treasure might not stay buried, but be received and enjoyed, God has caused the Word to go forth and be proclaimed. In the Word, He has the Holy Spirit bring this treasure home and make it our own. Therefore, sanctifying is just bringing us to Christ so we receive this good which we could not get ourselves” (Large Catechism, II:38–45).
God the Father so loved the world before anything was ever created, that He chose us and ordained to send His Son, who is the only begotten God from eternity, into the world to save us by the shedding of His blood. And God the Father and God the Son sent God the Holy Spirit so that He would sanctify us and deliver the benefits of that saving blood of God the Son to us now. God the Father so loved the world that He gave His only begotten Son, that whoever believes in Him through the sanctifying work of the Holy Spirit should not perish but have everlasting life (John 3:16). To you, elect according to the foreknowledge of God the Father, in sanctification of the Spirit, for obedience and sprinkling of the blood of Jesus Christ, grace to you and peace be multiplied (1 Peter 1:1–2).
This is the truth concerning the one and only almighty and everlasting God, Father, Son, and Holy Spirit. This is the one of whom the Scripture speaks, when it is written, “You shall have no other gods,” or “There shall be no foreign god among you, nor shall you worship any foreign god” (Exodus 20:3; Psalm 81:9). This is the Catholic faith, the universal Christian faith concerning the one true God that must be kept whole and undefiled, must be believed in the heart if one desires to be saved.
We have what God reveals to us in Sacred Scripture concerning Himself, which He says, “Hear, O Israel: The Lord your God, the Lord is one. You shall love the Lord your God with all your heart, with all your soul, and with all your strength” (Deuteronomy 6:4–5). We have that oneness of God taught clearly in Scripture, and alongside this truth concerning the oneness of God, we have the clear testimony of Scripture from the Baptism of Christ, where the Father speaks from heaven, the Holy Spirit descends in the form of a dove, and Jesus the Son from eternity is standing there in the water, each one subsisting in themselves (Matthew 3:16–17).
So we have this clear testimony. We have the testimony of the institution of our own Baptism, where Christ commands His apostles to baptize “in the name [singular] of the Father, and of the Son, and of the Holy Spirit” (Matthew 28:19), and the fact revealed in Christ’s farewell speech to His disciples in John 14 to 17, that along with the Father and the Son, the Spirit also has personality and is not a mere energy or force. He testifies of the Son, and energy doesn’t testify; a person testifies. He comforts; a person comforts, and He convicts the world concerning sin, righteousness, and judgment. That is something a preacher, a person does, not a force.
So you have the oneness of God clearly taught in Scripture, and this plurality, this threeness of God clearly taught in Scripture, both alongside one another. And this is the point of the Athanasian Creed that is repeated over and over again: “We worship one God in Trinity, and Trinity in Unity, neither confusing the persons, the threeness, nor dividing the substance, the oneness. For the Father is one person, the Son is another, and the Holy Spirit is another, but the Godhead of the Father and of the Son and of the Holy Spirit is one, the glory equal, the majesty co-eternal” (Athanasian Creed, 3–6).
Each person, the threeness, each person is uncreated, infinite, eternal, and yet there aren’t three uncreated infinites or eternals, there is only one. “Hear, O Israel: The Lord our God, the Lord is one” (Deuteronomy 6:4), is believed at the very same time as the clear teaching that the Father is God, the Son is God, and the Spirit is God, yet there are not three gods, but one God. Believing in any other God than this will result in eternal damnation, period. The only God, the only name under heaven by which we must be saved (Acts 4:12).
If that is the case, and it most certainly is, that trusting in the triune God alone will save a person, and trusting in any other God or gods will result in everlasting destruction, if that is true, then the Old Testament must teach us concerning the triune God, because both Testaments in and of themselves are perfect and sufficient. As Abraham is going to tell us next week in the parable of the rich man and Lazarus, when the rich man is coming to Abraham, begging him to send Lazarus back from the dead, to warn his five brothers so that they don’t go to hell with this rich man, Abraham says to him, “They have Moses and the prophets; let them hear them. If they do not hear Moses and the prophets, neither will they be persuaded though one rise from the dead” (Luke 16:29, 31).
This tells us, Jesus tells us in this parable in no uncertain terms, that even if a person only had access to the Old Testament, they would have exactly what they need to know and believe in the heart from those words alone of Moses and the prophets, to have eternal life and avoid the fires of hell. Even if all they had were the Old Testament Scriptures.
This is something that is denied by many who call themselves Christians today. On the one hand, Mormons and Jehovah’s Witnesses claim that the teaching concerning the Trinity is an invention of the early church. On the other, Roman Catholics claim the doctrine of the Trinity is a proof in support of an infallible, sacred tradition that not only includes the Bible, but also the Pope and Magisterium, or teaching authority, of the Roman Catholic Church, as it’s manifested in papal statements and church councils. They use it as a proof since the word “Trinity” isn’t in the Bible, and because early Christians struggled with the doctrine, and so they conclude, if it were so hard for them to figure out, the Bible must not be enough on its own to teach us what we need to know about the triune God.
Against this, our Lord Jesus says, not only are the Old and New Testament Scriptures more than enough to understand who God is, but even the Old Testament on its own is enough for a Christian to have a right knowledge concerning the blessed Trinity. That is what’s taught in the parable of the rich man and Lazarus that we will hear next week. It’s what’s taught when Paul says, “All Scripture is profitable for teaching, for reproof, for correction, for training in righteousness, that the man of God may be complete, equipped for every good work” (2 Timothy 3:16–17). He’s not talking about the New Testament, because only a few letters are floating around. When he says Scripture there, he’s talking about Moses and the prophets, and it’s enough to make a man complete, a man of God complete and perfect and equipped for every good work.
To show this truth to you, and to give you a place to start in your own studying of God’s Word concerning the Trinity in the Old Testament—and it is just a place to start—I want to present to you proofs of the Trinity in the Old Testament coming from four different perspectives: Creation, the Exodus, the promise of the Messiah, and the Aaronic Benediction, the blessing that you’ll hear at the end of Divine Service. And I’m stealing this from Johann Gerhardt in his work on the most holy mystery of the all-hallowed and ineffable Trinity.
So from creation, the Trinity. “In the beginning God created the heavens and the earth” (Genesis 1:1), but how did He create? It says, “God said, ‘Let there be light’” (Genesis 1:3). His Word brings light from darkness. “By the Word of the Lord the heavens were made, and all the host of them by the breath of His mouth” (Psalm 33:6). And that Word, like the Spirit, is not an impersonal force. Proverbs 8 personifies this Word: “The Lord possessed Me at the beginning of His way… I was beside Him as a master craftsman” (Proverbs 8:22, 30). And we know from John 1, the memory verses for this week, that Christ Himself is the eternal Word by whom all things were made (John 1:1–3).
And while the Word speaks, and God said, “Let there be light,” before this in Genesis you hear, “the Spirit of God was hovering over the face of the waters” (Genesis 1:2), not as a poetic symbolic image, but as the divine life giver, the Lord and giver of life. Job confesses, “The Spirit of God has made me, and the breath of the Almighty gives me life” (Job 33:4). So even in the beginning, the Father creates, the Word acts, and the Spirit gives life.
Even the very first sentence of Scripture hints at this divine mystery in the very words themselves, in the grammar of it. When it says, “In the beginning God created,” the word for God is a plural word, Elohim is plural, “gods.” In the beginning, God, plural, is paired with created, a singular verb. And then you’ve probably already heard, “Let Us make man in Our image” (Genesis 1:26). And some say, well that’s just the royal “we,” like when a king says “us” when he’s talking about himself, or a celebrity is talking in the third person. But then you’ve got to ask, where would that come from? Why in human language do we have some notion of a royal “we,” if it were not for the fact that the source of all language, God Himself, did not write that into it from the start? So in the beginning, God, plural, created, singular. You have the plurality and the oneness even in the grammar. So that’s creation, and that’s just a start.
In the Exodus, when the Lord delivered Israel from Egypt, it was not only the Father at work. In Isaiah 63, the prophet recounts that “He became their Savior,” and then says “the Angel of His Presence saved them. In His love and in His pity He redeemed them” (Isaiah 63:8–9). This angel, literally messenger, is not a created being. He is God’s own presence, His own face, appearing and saving. And then Isaiah goes on in the next verse to say, “They rebelled and grieved His Holy Spirit” (Isaiah 63:10). Here is not only the saving Angel, the pre-incarnate Son of God, but also the Holy Spirit grieved by their rebellion. All three persons are at work: the Father who sends, the Son who redeems, then the Spirit who is grieved. Not three gods, but one God in three persons.
And then the promise of the Messiah. The Messiah of the Old Testament is not merely a future man empowered by God, like David or Solomon. He is truly God. God says of the Messiah, “The Lord said to my Lord, ‘Sit at My right hand’” (Psalm 110:1). He puts those words into David’s mouth to say that the Messiah is not just descended from David according to the flesh, but is his Lord, Yahweh, I AM. The Messiah is David’s Lord, not merely David’s son.
Isaiah prophesies that the child born to us will be called “Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace” (Isaiah 9:6). Not names given to a mere man. He bears the names and attributes of God Himself. The Messiah performs the works of God. He judges the nations, forgives sins, establishes an everlasting kingdom, as Daniel 7 says, and is worshiped. He is not merely promised, He is already present.
In Joshua 5, the commander of the army of the Lord appears. Joshua falls on his face to worship him, and unlike mere angels, this one, this commander of the armies of the Lord, doesn’t stop him. Like if you read Revelation when John falls down before the angel, and he says, “You must not do that! Worship God only” (Revelation 19:10). The commander here of the armies of the Lord does not stop him when Joshua falls on his face to worship him. Instead, he commands him the same words that are commanded by God at the burning bush, “Take your sandal off your foot, for the place where you stand is holy,” just as the Lord did there at the burning bush (Joshua 5:15; Exodus 3:5).
And Isaiah 48:16 is perhaps the clearest Trinitarian verse in the prophets: “Come near to Me, hear this: I have not spoken in secret from the beginning; and now the Lord God and His Spirit have sent Me.” Who is the one speaking? He speaks as God from the beginning, and yet says He has been sent by the Lord God and His Spirit. The speaker is the Son who is eternally begotten and now reveals Himself in His mission with the Father and the Spirit. So the promise of the Messiah, just to start.
And finally the Aaronic Benediction. In Numbers 6, the Lord commands Aaron to bless Israel with these words that you’ll hear at the end of the service: “The Lord bless you and keep you; the Lord make His face shine upon you, and be gracious to you; the Lord lift up His countenance upon you, and give you peace” (Numbers 6:24–26). Why three? Why this threefold blessing? It’s for distinction: the blessing of the Father who keeps, the grace of the Son whose face shines, like the hymn “O Morning Star, How Fair and Bright,” or Peter’s words from Scripture, “the day star shines upon our hearts,” talking about the Son coming again, and the peace of the Spirit who reconciles. This is the same shape we hear in the Apostolic Benediction: “The grace of our Lord Jesus Christ, the love of God, and the communion of the Holy Spirit be with you all” (2 Corinthians 13:14).
Why not come up with fourfold, or a fivefold, or a sixfold? Why three? That threefold pattern is in our Old Testament reading this morning too. Why are the angels singing to the Lord, “Holy, holy, holy,” and not “holy is the Lord,” or “holy, holy,” or “holy, holy, holy, holy,” or some other number? Why three? Over and over again, why? And when Isaiah sees the Lord enthroned in glory, John tells us in John 12:41 that Isaiah said these things when he saw His glory and spoke of Him, referring to Christ. The Lord whom Isaiah saw was the pre-incarnate Son. You’ve got it all there, and in Revelation 4 through 5 you’ll hear it again, the heavenly worship echoes the pattern: the Father on the throne, the Lamb who is worshiped with Him, and the sevenfold Spirit before the throne.
What Isaiah saw envisioned, John saw fulfilled in Christ, the Lamb. The God of the Old and New Testaments is one God, and He clearly reveals Himself to us in every part of Scripture as the One who loved us and chose us to be saved from before the foundation of the world, the One who sent His beloved Son to pour out His blood for us, the One who gives the Holy Spirit to take us out of slavery and death in the devil's kingdom and place us into the kingdom of grace. All who call upon the name of this triune Lord of all in true faith will be saved (Romans 10:13).
The doctrine of the Trinity is not just something where we can check off a book and say, see, we got it right. That's not the point of any article of doctrine in any part of the Book of Concord, any part of Scripture. It's not the point.
The doctrine of the Trinity, that God is one, strikes at the heart of the truth of Scripture. If you cannot trust the words of Scripture that tell you that God is one, then you cannot trust the words of Scripture that say your sins have been paid for. If you cannot trust the words of Scripture that say the Son and the Father and the Spirit are all God and yet they're one God, same thing.
You can't trust the words of Scripture when they give any other promise. And on top of that, if you do not believe in the heart that the Father is truly God, the Son is truly God, and the Spirit is truly God, then the works that Scripture tell us each of these persons performs as the one true God cannot be trusted in fully. If the Son is not truly God, we cannot trust that His blood actually, infallibly, pays for our sins and washes them away (1 John 1:7).
If the Spirit is not truly God, then you cannot trust that He's going to perfectly and infallibly testify of Christ and convict the world concerning sin, righteousness, and judgment (John 16:8). You cannot trust it completely as you're called to trust completely in God. And even the Father, if you do not trust completely that He is truly God, then the fact that He elected us for salvation is not something you can trust in with your whole heart, because He might be wrong.
It isn't fully perfect and complete and infallible. But we are assured of that fact from God Himself, that "the Lord your God is one," and His name, "I AM," is shared by each of the three persons, Father, Son, and Holy Spirit (Deuteronomy 6:4; John 8:58). And we can fully trust in this blessing that Peter first spoke to the church that you need to hear now for yourself.
"You elect according to the foreknowledge of God the Father, in sanctification of the Spirit, for obedience and sprinkling of the blood of Jesus Christ," the perfect work of election, of the sprinkling of blood and sanctification, that perfect work which belongs to you, accomplished by your Lord. Because of that, grace to you and peace be multiplied (1 Peter 1:2).
Let us pray. Almighty and eternal God, God the Father, God the Son, God the Holy Spirit, You have shown Your rich grace and mercy to us. Eternal Father, You created us at the beginning. Eternal Son of God, for us You became fully human, and for our sins You bore the cross. Eternal Spirit, You proceed from the Father and the Son from eternity, and through Your holy Gospel You give us faith and holiness. O one, eternal and almighty God—Father, Son, and Holy Spirit—keep us in Your grace until our life’s end in the eternal blessedness of the life to come; for You live and reign, one true God, now and forever. Amen.
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