Generally commemorated on June 14 in the ELCA breviary with the other two Cappadocian Fathers ( he and the other two Gregorys... of Nyssa and of Nazianzus), Basil is commemorated today in the Roman calendar, and frankly given the importance of these three, each really should receive their own date. Butler's Lives of the Saints says,
Basil the Great lived during the height of the Arian controversy (239-379), and he had an important part in the process of resisting it.... Basil worked against steady opposition and received little support from other leaders in the Church even as he was championing the Church's teachings. Libraries preserve many of his books and letters today. The members of his flock loved him because he was an outstanding pastor who often visited among them. He preached to large gatherings twice a day, took care of the poor, and had a hospital built. One of the great personalities in church history, Basil did superlative and enduring in one of the most difficult times the Church has ever faced.Briefly, Arias and his school taught that ultimately that the Son (Trinitarian language) was a creature far surpassing any other creature of the world, but made nonetheless by God the Father. The Son merely becomes a demigod and loses actual knowledge of God, which if God is truly transcendent, no mere creature however exalted, could know.
Basil offers an example not just of the defense of the faith, but of perserverance in the faith. In a world where everyone expects a quick fix, or maybe a compromise, Basil reminds us that there are some things worth staying in for the long haul. Had the Church compromised on this doctrine, something essential would have been lost. Jesus as the Son of God is important not because he is another creature like one of us, but because he is God who dwells with us carrying knowledge (not mere information, but relational knowledge) of the Father and Spirit. If there was a time when the Son was not (which Arias taught since the Son was made by the Father), then there is no way to claim that the Son shared divinity in any meaningful sense.
Let us all perservere in the faith.