Modalistic Monarchianism

Modalistic Monarchianism, also known as Modalism or Oneness Christology, is a Christian theology upholding the oneness of God as well as the divinity of Jesus. As a form of Monarchianism, it stands in contrast with Trinitarianism. Followers of Modalistic Monarchianism considers themselves to be strictly monotheistic, similar to Jews and Muslims. Modalists consider God to be absolutely one and believe that He reveals Himself to creation through different "modes" (or "manifestations"), such as the Father, Son, and the Holy Ghost, without limiting His modes or manifestations. The term Modalism was first used by Trinitarian scholar Adolf von Harnack, referencing this belief.

In this view, all the Godhead is understood to have dwelt in Jesus from the incarnation as a manifestation of Yahweh of the Old Testament. The terms "Father" and "Son" are then used to describe the distinction between the transcendence of God and the incarnation (God in immanence). Lastly, since God is a spirit, it is held that the Holy Spirit should not be understood as a separate entity but rather to describe God in action.

Modalistic Monarchianism is closely related to Sabellianism and Patripassianism, two ancient theologies condemned as heresy in the Great Church and successive state church of the Roman Empire.