Modalism is a theological doctrine that emerged in the early Christian church, particularly in the 2nd and 3rd centuries. It is a form of Monarchianism, which refers to a group of theological beliefs that emphasize the unity of God and deny the existence of distinct persons within the Godhead.
Modalism, also known as Sabellianism or Modalistic Monarchianism, teaches that God is a singular entity who reveals Himself in different modes or manifestations at different times. According to this doctrine, God the Father, God the Son (Jesus Christ), and God the Holy Spirit are not distinct persons but somewhat different expressions or roles that God assumes at different historical points.
In modalism, God is seen as operating in three modes or masks rather than as three distinct persons. For example, during the Old Testament, God operated in the mode of the Father, while during the incarnation of Jesus Christ, He operated in the mode of the Son. After Jesus' ascension, God operates in the mode of the Holy Spirit.
Modalism was considered heretical by mainstream Christian theologians because it conflicted with the doctrine of the Trinity, which affirms the existence of three distinct persons within the Godhead: the Father, the Son, and the Holy Spirit. The orthodox understanding of the Trinity maintains that these three persons are co-eternal and co-equal yet distinct in their personhood.
The controversy over modalism contributed to the development of the doctrine of the Trinity and the formulation of creeds such as the Nicene Creed, which clarified the orthodox understanding of the nature of God. Modalism continues to be rejected by most mainstream Christian denominations as a deviation from the orthodox understanding of the Trinity.
