The Arian heresy and the nature of the Church
The Arian controversy was significant for the Church in many respects. One of them being the doctrinal development of God. The early Church realized that Scripture alone was not sufficient to irrefutably explain the Trinitarian doctrine. The Church needed to recourse to philosophy and exegetes to understand Scriptures in a Trinitarian context. However, that is not to say that in doing so the integrity of the message contained in Scriptures would be compromised by using philosophical terms that would explain God’s nature in ontological terms. The problem was that Scripture passages alone—isolated from proper exegesis—did not suffice to explain the relationship between the Father and the Son, because they often contradicted each other as the passages of distinction (“No one is good, but God alone”–Mk 10:8) contradicted those of identity (“The Father and I are one”–Jn 10:30), for instance. Therefore, from a doctrinal development standpoint, the Arian controversy was crucial in demonstrating how essential Tradition was for the Church.
Of course, the divinity of the Son was at stake in the Arian controversy, which was of prime importance for the Church to refute. To agree with Arius and make Jesus part of creation—the first creature—was to put salvation in question (how can a creature save creation itself?). Moreover, Arianism tested Christian monotheism and the Church itself, because since Her beginnings She worshiped Jesus Christ. As a result, if Jesus was merely the first creature, the Church could have been worshiping a creature. On the other end, to fail to distinguish the Father from the Son could give room to Patripassianism which was the concern of those who did not agree with the homoousios (“of same substance”).
The Arian controversy had many political ramifications which led to many bishops and Emperors to support the Arian cause. Whenever Arianism enjoyed imperial support, the bishops of the Nicene party were threatened, banished, and exiled, which weakened the Nicene cause temporarily. However, Nicea was finally confirmed in the Council of Constantinople in A.D. 381 in which the divinity of the Son was also added to the Holy Spirit.
One can then conclude Arianism tested the Church at her very core—questioning the very belief that founded Her. Although the victory of the Nicene party was not easy, the process of doctrinal development and theological advances—headed by Athanasius, Alexander, Gregory of Nyssa, Gregory of Nazianzus, and Basil—were perhaps needed for the Church to understand Her authority and the importance of Tradition in order to define irrefutably the Trinitarian doctrine.