The Trinity can be summarized in three statements supported by Scripture. Any belief or movement or person who alters one of these Scriptural views is unsound Biblically. These three Biblical summaries refute Modalism, Jehovah Witnesses, and Mormonism.
God is Three Persons
This Biblical summary refutes modalism or the belief that God is one person manifested in three modes. Sabellius, an African bishop, in the third century taught modalism. In the Old Testament God was manifested as the Father, in the Gospels, as Jesus, and today as the Holy Spirit, according to modalism.
One Pentecostalism denies the three persons of the Trinity and is modalistic. David K. Bernard represents this heresy in his The Oneness of God: The Oneness position is “the doctrine that God is absolutely one in numerical value, that Jesus is the one God, and that God is not a plurality of persons….The Father, Son, and Holy Spirit are three manifestations of the one God” (pages 321-322; 142-143).
T. D. Jakes, who grew up in Oneness Pentecostalism, on his website’s doctrinal statement, makes a similar modalistic statement about God: “There is one God, Creator of all things, infinitely perfect, and eternally existing in three manifestations: Father, Son, and Holy Spirit.”
In contrast to this aberrant view on the Trinity, the Scriptures teach that the Son is not the Father. In John 17:24, Jesus is praying to the Father who therefore must be distinct from the Son. In 1 John 2:1, Jesus is the advocate with Father, not synonymous with Him. The Holy Spirit proceeds from the Father in John 14:26. In John 16:7, Jesus says He will send the Holy Spirit, consequently the Holy Spirit cannot be the Father nor the Son. Not only are there three persons in the Trinity but each person in the Trinity is fully God.
Each Person of the Trinity is Fully God
The Jehovah Witnesses, in the book Should You Believe in the Trinity?, make a clear denial of the deity of Christ: “The entire testimony of the entire Bible is that Jesus is not Almighty God” (page 28).
The entire testimony of Scripture, however, is that each person of the Trinity is equally God. God the Father is fully God (Ephesians 4:4-6), as well as God the Son (Colossians 1:19) and the God the Spirit (Acts 5:1-4). While God is three persons and each person of the Trinity is Deity, there are not three gods. There is one God.
There is One God
Tritheism is “the perversion of the doctrine of the Trinity, propounding the theory that there are three Gods, distinct in essence, not one God in three personal subsistences” (Alan Cairns. Dictionary of Theological Terms, Belfast and Greenville: Ambassador –Emerald International, 1988, 417). Mormonism is an example of tritheism.
Rex Lee, president of Brigham Young University wrote the three persons of the Trinity are not one being but are “separate individuals” and the also that the Father has a physical body “of flesh and bone” (What Do Mormons Believe, Salt Lake City: Deseret Book, 1992, 21).
The oneness or unity of God was the emphasis of the Old Testament while the threeness of God is the emphasis of the New Testament: Matthew 3:16-17; 28:19-20; the Trinity is found eight times in Ephesians (1:3-14; 1:17; 2:18; 2:22; 3:4-5; 14-17; 4:4-6; 5:18-20).
Is the threeness of the Trinity in the Old Testament? Yes. In Isaiah 63:7-10 are the three persons of the Trinity. The Trinity is also found in Isaiah in 48:16 and 61:1.
The New Testament, however, will emphasize the three persons of the Trinity because of progressive revelation and because Jesus, the second person of the Trinity, came to earth.
The emphasis on the oneness or unity of God begins with the first verse in God’s Word which declares “In the beginning God [not gods] created the heavens and the earth.” “God” or Elohim is a plural of majesty not number (Charles Ryrie, Basic Theology, page 207). Deuteronomy 6:4 demands God’s Old Testament people to “Hear, O Israel: The Lord our God, the LORD is one” which was repeated by Christ in Mark 12:29. To worship any other God is idolatry (Exodus 20:3).
The reason for the emphasis on the oneness or unity of God in the Old Testament in Deuteronomy 6:4 was Israel’s propensity for idolatry or the worship of many gods. The context of Deuteronomy 6 makes clear this weakness. After Israel is commanded to worship God who is one, God commands in 6:14, “You shall not go after other gods, of the gods of the people which are round about you; (For the LORD your God is a jealous God among you) lest the anger of the LORD your God be kindled against you, and destroy you from off the face of the earth.”
These three summary statements on the Trinity represent orthodox Christianity. Arius, a pastor in Alexandria, said Christ was similar to the Father but not the same in the early 300s. One pastor in particular battled Arianism. Athanasius, almost singlehandedly battled for the truth of the Trinity in the fourth century and was exiled five times for 17 years for his relentless stand. Largely because of the influence of Athanasius the Council of Nicea met in 325 A.D. with 318 Christian Leaders and declared Jesus “of one substance with the Father.” We should not take this great doctrinal truth for granted but teach and preach it even in the face of growing anti-trinitarian views.