EFS has overlooked that the blueprint of biblical ethics is not the ineffable eternal relations of the Trinity, but the word of our Lord who is one. “The Scriptures ground ethics upon metaphysics, for God’s supreme authority to command our trust and obedience derives from his supreme being – who and what he is.” There are no scriptural texts where our duty before God is rooted in the Son’s eternal obedience to the Father in God. Scripture, however, regularly bases our moral obligations upon His simple unity as God. The Shema of Deuteronomy 6:4 is the rationale for the Great Commandment to “love the LORD your God” (v. 5) and to teach His laws to succeeding generations (vv. 6-7).

Western culture today parades its rebellion against nature and our Creator, against the goodness of bearing God’s image as men and women. Christians must defend the Bible’s teaching on God’s design for both sexes and how each complements the other. Many, however, do so by arguing that our roles and relationships as men and women are patterned after the Trinity itself,[1] specifically in the Father’s authority over the Son in an “Eternal Functional Subordination” (EFS).[2] While I agree with many EFS proponents on the biblical order for the home and the church, there is a tragic irony to their method. By implicitly dividing our simple God, they undermine the foundation of the very scriptural ethics that they endeavor to preserve.

The Simple Unity of God

Scripture emphatically cuts against humanity’s penchant for polytheism.[3] The basic confession of God’s people was the Shema, “The LORD our God, the LORD is one” (Deut 6:4). If our Lord is an exclusive, singular unity, He must therefore be a simple unity.[4] If the One who created all things is composed of any things (or parts) prior to Him, then it could not be said that He created all things (Gen 1:1; Rom 11:36). In the 17th century, Edward Leigh explained:

God is absolutely Simple, he is but one thing, and doth not consist of any parts… If he did consist of parts, there must be something before him, to put those parts together; and then he were not Eternal.[5]

Divine simplicity is why Scripture not only describes qualities God has but uses substantives to say what He is, as in “You are good” (Ps 119:68) and “God is love” (1 John 4:8).[6] When God told Moses “I AM who I AM” (Exod 3:14-15), He revealed His peerless nature by His name, “Yahweh” (usually represented by “LORD” in English), something of a pun on “I AM.”[7] God’s essential name means He is “Being itself,”[8] “an Absolute Being, nothing but Himself,” so that “whatsoever you can say of God, is God.”[9] As the One who is (cf. Rev 4:8), God is exalted above any possibility of cause, change, chronology, or categorization.[10] Creatures are divided into individual beings who can be grouped with others who share their nature, as members of a common species. How can this be true of the Creator of all natures? How could He come to exist in a category that is prior to Him with peers who are like Him? “It is thus divine simplicity that undergirds monotheism and ensures that it does not just so happen that God is one, but it must be that God cannot but be one being because of what it means to be God.”[11] There is no one like our simple God (Isa 44:8).

When He spoke to us by His Son, the Lord revealed that He is a simple being who exists as Father, Son, and Spirit. So, Paul could ascribe Israel’s Shema to the Father and the Son, who are “one” and who created “all things” (1 Cor 8:4-6; cf. Col 1:16; Jn 1:3). As the early church reflected on such texts, they understood that “[t]he generation of the Son and the breathing of the Spirit thus occur within the bounds of the divine simplicity.”[12] In other words, “The persons are not different things from that thing which is the divine essence.”[13] God simply is the Father begetting the Son and, with the Son, breathing forth the Spirit.[14] Divine simplicity, far from being inconsistent with the Trinity, is in fact its “lynchpin.”[15] How else could we be kept from thinking of the Father, Son, and Spirit as individual beings of a divine species like creatures?[16] Or even as a council of deities that we have just named “God”?[17] God is Triune, not in spite of His simplicity, but because of it. Swain put this plainly:

there was and is no need for the doctrine of the Trinity if God is not simple, for there were and are plenty of sophisticated and unsophisticated ways of conceiving how three persons may comprise one complex divine being or community.[18]

So, if we think about the Trinity in mathematical terms, we do not need to say “three” (as if the persons are individual beings of a divine species). We can always say the Father is God, the Son is God, and the Spirit is God. However, if we do not say that God is “one,” then we would be saying little more than polytheists say about their deities.[19] In order to count to the true and Triune God, the essential number is one.

The Divided Community of EFS

While EFS advocates undeniably affirm the exclusive unity of God, their modern revision of the Trinity endangers it. Theology requires, as Sinclair Ferguson has written, that we “point out the logical implications of presuppositions.”[20] EFS logically entails the division of our simple God in more than one way, ignoring Calvin’s warning not to “think God’s simple essence to be torn into three persons.”[21]

First, God’s indivisible unity means that whatever we say of God’s nature is equally true of the Father, the Son, and the Holy Spirit, and that includes His will and authority.[22] By His will and power, Scripture identifies God as God, “I am God, and there is no one like me… My purpose shall stand” (Isa 46:9-10). So, each Person exercises that divine will inseparably from the other two as God.[23]

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