Homoousios

Definition and Meaning

The Greek term homoousios combines homos, meaning "same," and ousia, meaning "essence" or "substance." Essence refers to the very being that makes God God. The term expresses the confession that the Son, Jesus Christ, is neither a being merely similar to the Father nor a creature made by the Father, but is true God just as the Father is. It was rendered in Latin as consubstantialis. In Korean it is rendered as dongil bonjil ("same essence"), dongjil, or han bonche ("one substance"), and in English it is commonly translated "consubstantial" or "of one substance" (or "of one being") with the Father.

At the same time, the Father and the Son, while sharing the same essence, are distinct persons (personal subjects). This confession therefore differs from modalism, which holds that the one God appears in different modes at different times.

Biblical and Historical Background

The word itself does not appear in Scripture. The church used the term to summarize passages that speak of the divinity of Christ, such as John 1:1, John 10:30, Philippians 2:6, and Hebrews 1:3.

In the early fourth century, Arius, a presbyter of Alexandria, taught that the Son was a being created by the Father (Arianism). The Council of Nicaea, convened by Emperor Constantine in 325, rejected this teaching and included in its creed the statement that the Son is "of one substance with the Father." Even after the council, objections that the word was not found in Scripture, along with arguments for a "similar essence" (homoiousios), kept the controversy alive for decades. Athanasius is known as the figure who defended the term steadfastly throughout this period. The Council of Constantinople in 381 reaffirmed the Nicene confession, which became the basis of today's Nicene Creed. The Council of Chalcedon in 451 confessed that Christ is consubstantial with the Father according to his divinity and consubstantial with us according to his humanity.

Practice in the Korean Church

All the major Protestant denominations in Korea accept the Nicene confession of the Trinity. Consequently, there is little disagreement among denominations over the meaning of the term; the differences lie mainly in how the confession is used in worship.

• Anglican and Lutheran churches: The Anglican Church of Korea and the Lutheran Church in Korea are known to confess the Nicene Creed in their eucharistic services.
• Presbyterian, Methodist, and other denominations: Presbyterian, Methodist, Holiness, Baptist, and Full Gospel churches generally confess the Apostles' Creed in Sunday worship, and the Apostles' Creed does not contain this expression. These denominations address the concept in seminary education and doctrinal instruction. The Westminster Confession of Faith, the doctrinal standard of Presbyterian churches, confesses that the three persons are of one substance. Article II of the Methodist Articles of Religion, as prepared by Wesley, describes the Son as "of one substance with the Father."

The concept also serves as a standard in controversies over heresy in the Korean church. For example, Jehovah's Witnesses regard Jesus as the first being created by God. The major Korean denominations and heresy researchers have criticized this view as a departure from the Trinitarian confession held since Nicaea. Jehovah's Witnesses, for their part, argue that the Trinity and the concept of consubstantiality are later philosophical doctrines not found in Scripture.