The One God
Christian confession begins with the Shema: “Hear, O Israel: The Lord our God, the Lord is one” (Deut. 6:4). This is not only a declaration of monotheism, but also a testimony to the undivided unity of God’s being. He is not composed of parts. He does not shift between moods. His love and justice, His holiness and mercy, are never at odds. God is one, simple, and whole.
The church has long described this truth with the doctrine of divine simplicity. Though the term may sound philosophical or abstract, its purpose is deeply pastoral. Simplicity assures us that God’s character is perfectly consistent, that His attributes are not in competition, and that His being is undivided and whole.
Far from an intellectual curiosity, divine simplicity is the foundation of our confidence in God’s unchanging faithfulness. If God were fragmented or internally conflicted, we could never trust Him fully. But because He is simple, His promises are sure, His love unwavering, and His justice always true.
God’s Undivided, Unified Nature
To say that God is simple is to say that He is not composed of parts. Human beings are complex: our thoughts can be divided, our emotions conflicted, our lives fragmented. God is not like us. His attributes are not components that come together to form His essence. They are identical with His essence.
Thomas Aquinas expressed this clearly: “God is simple, for in Him there is no composition.”1 Louis Berkhof echoes the point, describing simplicity as “that perfection of God whereby He is free from all composition or parts.”2 In other words, whatever God has, He is. His holiness, wisdom, justice, and love are not additions to His being. They are His being.
Scripture provides the foundation for this truth. God declares, “I AM WHO I AM” (Exod. 3:14), revealing His absolute, unqualified existence. John reminds us that “God is spirit” (John 4:24), not composed of body or matter. And the apostles declare that “God is light” (1 John 1:5) and “God is love” (1 John 4:8). These are not mere descriptions of qualities that God possesses. They are statements of identity. God simply is who He is.
The Harmony of God’s Attributes
Modern discussions about God often pit His attributes against one another. People ask whether God is more loving than just, or whether His mercy tempers His wrath. These questions betray a fragmented view of God.
Divine simplicity reminds us that God’s attributes are not competing forces within Him. They are perfectly unified in His being. God’s love is a just love, and His justice is a loving justice. His mercy does not compromise His holiness, nor does His holiness diminish His compassion.
Herman Bavinck observes, “In God, too, all things are one. Justice and mercy, love and wrath, are not separate parts or faculties but one, in His simple, undivided being.”3 This means that when God acts in justice, He is not setting aside His love. When He acts in mercy, He is not abandoning His holiness. Every act of God reflects the wholeness of who He is.
This truth guards us from projecting our own divided personalities onto God. We experience inner conflict between desire and duty, compassion and judgment. God does not. He is always and entirely Himself.
Clarifying Misunderstandings
Because the language of simplicity is less familiar today, it is often misunderstood. Some worry that it makes God sound like an abstract concept rather than a personal being. But simplicity does not deny God’s personhood. It protects it. God is not less than personal; He is perfectly personal, without the inner fragmentation that mars human life.
Others suggest that simplicity is a philosophical imposition on Scripture. Yet the doctrine arises from biblical affirmations of God’s unity, immateriality, and aseity. The church’s reflection on simplicity was not an attempt to add something foreign to revelation, but to confess faithfully what Scripture already teaches.
Finally, some claim that if God is simple, He cannot genuinely relate to His creatures. But in fact, simplicity secures the opposite. Because God’s love is not an attribute He merely possesses but His very being, we can be confident that His love is never diminished or inconsistent. His promises are not conditioned by moods or changes within Himself. They are grounded in His simple, eternal nature.
The Security of God’s Consistent Character
Divine simplicity matters because it secures the unity and consistency of God’s character. We can trust Him fully because He is never conflicted, never double-minded, never divided against Himself.
This truth leads to assurance. The God who justifies us in Christ is the same God who sanctifies and glorifies us. His justice does not cancel His mercy, and His holiness does not compete with His love. All of His perfections are one, and all are perfectly inclined toward His people in Christ.
It also leads to worship. We do not praise a fragmented deity, merciful one day and wrathful the next. We worship the one God, Father, Son, and Spirit, undivided in essence and consistent in all His ways.
And it leads to discipleship. Because God is not divided, we need not fear that one part of Him will turn against another. He is whole and unified, and therefore His purposes are entirely trustworthy. As Paul declares, “He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things?” (Rom. 8:32).
Conclusion
The doctrine of divine simplicity may not seem immediately practical, but in truth, it is one of the most pastorally significant truths of Christian theology. It assures us that God is never inconsistent, never divided, never conflicted. He is one.
This means that when God promises to save, we can trust that promise with all our hearts. The God who is just is also the God who justifies. The God who is holy is the God who draws near. The God who is love is the God who never changes.
Let us therefore confess with Israel of old and with the church through the ages: “The Lord our God, the Lord is one.” And let us rest secure in His undivided, unified, and faithful character.
Thomas Aquinas, Summa Theologica, I.3.7.
Louis Berkhof, Systematic Theology (Grand Rapids: Eerdmans, 1996), 58.
Herman Bavinck, Reformed Dogmatics, vol. 2, God and Creation, trans. John Vriend (Grand Rapids: Baker Academic, 2004), 177.