Monotheism and the concept of the Holy Trinity (i.e., three persons in one God) are not incompatible in mainstream Christianity and are, in fact, considered theological pillars in the evolution of the Christian Church. However, intense historical controversies and debates did exist concerning these initially divergent concepts that still persist to the present even among various Christian denominations Christian statistics. In the Catholic theological tradition, this divisive issue was addressed through the formation of various church councils that sought to unify and clarify the Church’s systems of beliefs as well as to denounce marginal and/or “heretical” teachings that are contrary to the dogmatic interpretation of the Church. Among the more potent products of these councils are the various Catholic creeds that distilled the fundamental tenets of Christian faith into prayer-like declarative texts that are meant to be memorized and recited by all the faithful. Prominent among these creeds is the Nicene Creed (325 AD) and its subsequent iteration called the Apostle’s Creed (ca. 390). Both creeds actively state the believer’s affirmation of the Trinitarian nature of God by invoking “God the Father, God the Son, and God the Holy Spirit.” In addition to adherents of Roman Catholicism, many Protestant denominations such as Anglicans, Lutherans, Episcopalians, and Methodists use the Apostle’s Creed in their liturgies.
From a fundamentally logical approach, to say that mainstream Christians are not monotheists because they worship three gods is almost unerringly valid. Based on its etymological roots, monotheism (from the Greek monos which means “single” and theos which means “god’) is the belief in the existence of one god. On the other hand, the root word for trinity is the Latin trinitas which means “the number three” or “a triad”. Unless juxtaposed in a special mathematical context, one and three are obviously unequal. As it turned out, the Christian juxtaposition is clever and simple: there are three Persons in one God. Monotheism is affirmed since there is only one God, and, at the same time, the triune attribute of God is declared without causing a logical break by depicting the essence of the singular God as composite of three divine persons.
For the Christian Church, the fusion of monotheism and the belief in the Holy Trinity underwent a remarkable evolution that took both Church authorities and adherents several centuries to arrive at a widely accepted resolution.
From the Biblical perspective, early Trinitarians posited the implicit revelation of the three Godheads in the Old Testament as well as the expressed statements in the New Testament by Jesus and the apostles intimating the holy nature of God as three persons. As claimed by James Oliver Buswell Jr, in fact, the idea of a Trinitarian deity has already permeated some parts of the Old Testament, that the Jewish people “saw no problem in the personal distinctions [italics rendered by this writer] in the being of God” even before the birth of Jesus Christ and the ascendancy of the apostles. Some Old Testament texts that introduce the triune nature of God include those that particularly refer to God’s word as in Psalms 33:6, His wisdom, and His spirit (see Isaiah 61:1). In some interpretations, the term spirit of the Lord commonly used in the Old Testament narratives is an actual reference to the Holy Spirit while the God’s Word is an identical term for the Son (i.e., Jesus Christ). As a side note, the New Testament Gospel of John clearly expresses the correlation at the very beginning of its text:
“In the beginning was the Word, and the Word was with God, and the Word was God”
While the Trinitarian revelation in the Old Testament is comparatively passive, its affirmation in the New Testament narratives is markedly conclusive. Many church historians in fact believe that the seed resource for the latter canonization of the Trinity principle by the more powerful and organized Church in the 2nd to the 4th centuries came from the Gospels and Paul’s epistolary works. To be sure, the term Trinity itself was never used in any of the New Testament books but the elements of early Christian greetings and sacraments were already replete with the idea of a triune God especially after the exact wordings of the Great Commission were attributed by the Gospel writers to the resurrected Jesus Christ, Himself. In addition, many of the introductory greetings in the epistolary works attributed to Paul are rich in Trinitarian invocations: “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all.” For some historians, the multiple instances wherein a Trinity of beings are alluded to in the New Testament texts constitute the gradual steering of the divine will to compel believers to affirm the existence and providence of the Holy Trinity within an enriched re-envisioning of a monotheistic faith.