Arius, a presbyter of the church in Alexandria, founded Arianism in the 4th century. The founder adopted Origen’s theory that stated that the Father alone is God in the highest sense. And he added that the Son is co-eternal with the Father, but “God” only in a derived sense. Arius denied that Jesus was the middle way between God and created beings.
Further, Arius taught that the Son is not divine but rather a creature and that therefore “there was [a time] when He was not.” He taught that only the Father is timeless and that He created the Son. To him, Christ was neither truly human because he didn’t have a human soul, nor truly divine, for He was without the characteristics of God. And he taught that the Father selected the human being Jesus because of His victory, to be the Christ.
The First Council of Nicaea
This council assembled in a.d. 325 to settle the Arian disagreement. Athanasius talked as “the father of orthodoxy,” taught that Jesus Christ always existed and was from the very same essence as the Father. He designated the term homoousios, “one substance,” to Christ, and the council confirmed that Christ is of one and the same essence as the Father. And the council condemned both Arianism and Sabellianism as unbiblical.
Also, the Nicene Creed stated that the Son is “begotten of the Father [… the essence of the Father, God of God], Light of Light, very God of very God, begotten, not made, being of one substance (ὁμοούσιον) with the Father” (cited in Philip Schaff, The Creeds of Christendom, vol. 1, p. 29). This creed became the crucial test of Trinitarian orthodoxy.
But the Arians rejected the decision of the council and were divided. Apollinaris and Marcellus were the main opponents of orthodoxy following the Council of Nicaea. These taught the true unity of the divine and the human in Christ but denied His true humanity.
Thus, these various opinions led to another council in the year 381, at Constantinople. And this council confirmed the Nicene Creed, explained its meaning, and acknowledged the presence of the two real natures in Christ.
In His service,