Denial that Father, Son, and Holy Spirit are separate Persons of the Godhead; claim instead that they are modes, aspects, energies, phases, or offices of a single divine Person.
Known as Sabellianism, after the third-century Roman priest Sabellius, who developed it, this heresy has had a number of other names, based upon different facets of the heresy and various conclusions that follow from it.
Sabellianism emphasized the fact that God is one, wrongly concluding that in the Godhead there is a single (mon-) principle or rule (-arche). Thus the heresy was also called “Monarchianism.”
Sabellians explained their position by saying that the Father, the Son, and the Holy Spirit are not three Persons, but three functions or modes of a single divine Person, so they also were called “Modalists.”
It was further recognized that if the Father, Son, and Holy Spirit were all “modes” of a single divine Person, it followed that the Father, being the same Person as the Son, suffered and died on the cross, and so in the West this heresy became known as “Patripassianism.”
How one divine Person could appear in three different ways could be explained by analogies: by appealing to the way an actor can play different roles in a play by wearing different masks; to the way water can exist in three different forms, solid, liquid, and gaseous; and to the way one man may have three separate roles as the son of one person, the husband of another, and the father of a third. Sabellius said that in God there are three modes in the same way that the sun is bright, round, and hot.
It is not clear whether the modes were thought of as things between which God switched back and forth (as in the mask and water analogies) or whether they were qualities exhibited simultaneously (as in the relationship and sun examples). Some Modalists claimed that when the redemption was finished, God would put away the three masks of the Father, Son, and Holy Spirit and manifest himself as a single-mode Person.
Sabellius was excommunicated by Pope Callistus I (c. 220). Sabellianism was rejected by the early ecumenical councils of Nicaea, Constantinople, Ephesus, and Chalcedon. These councils affirmed that God is one, but made the distinction between Person and nature, teaching that the Son and the Holy Spirit are separate Persons who share one divine nature with the Father.
In 382 the Council of Rome, with Pope Damasus I presiding, condemned the heresy, stating, “We anathematize those also who follow the error of Sabellius in saying that the same one is both Father and Son” (Tome of Pope Damasus, 2).
Important responses to Sabellianism were written by Tertullian (Against Praxeas) and Hippolytus (Against Noetus and Philosophumena). These authors pointed out absurdities implied by Sabellianism, such as that the Son must be his own Father.
(Side note: Hippolytus was then an anti-pope heading a schismatic congregation in Rome. Later he was reconciled to the Church and eventually was martyred.)
Sabellianism was revived at the time of the Reformation by Socinius, a Reformer considered a heretic even by other Protestants. Modalism arose in America during the nineteenth century and is today taught by several Pentecostal churches, the best known being the United Pentecostal Church (founded 1914).
Modern Pentecostal Modalists claim that “Jesus” is the proper name of the single divine Person who appears as the Father, Son, and Holy Spirit. This notion is also known as “oneness theology” or the “Jesus only” position. Its proponents tend to be active proselytizers. They reject baptism in the name of the Father and of the Son and of the Holy Spirit and instead baptize in the name of Jesus alone.