The Patristic Age of the early Church is a delightful mix of orthodoxy and struggle. Epiphanius was a friend of Jerome but found the mysticism of John Chrysostom to be a bit unorthodox. It is a time of chaos, of settling, of standardizing, and for determining how to talk about the Truths that had been revealed. Arianism and other heresies were rampant, causing upheaval, violence, and confusion. Epiphanius worked tirelessly to right the wrong thinking and to lead flocks of believers in the path.
This work to produce orthodoxy, where we accept some and question others, never stops and he shows us that it has been happening for a long time.
For his work we call him a Doctor of the Church, and we honor his desires and prayers to keep the Faith whole and true.
We believe in one God, the Father Almighty, Maker of all things, both visible and invisible; and in one Lord Jesus Christ, the Son of God, begotten of God the Father, Only-begotten, that is, of the substance of the Father; God of God, Light of Light, true God of true God; begotten, not made; con-substantial with the Father; through whom all things were made, both those in heaven and those on earth, both visible and invisible; who for us and for our salvation came down and took flesh, that is, was born perfectly of the holy ever-virgin Mary by the Holy Spirit, was made man, that is, He received perfect man, soul and body and mind and all that man is, except sin, not from the seed of man nor as is usual with men, but He reshaped flesh into Himself, into one holy unity; not in the way that He inspired the prophets, and both spoke and acted in them, but He was made Man perfectly; for "the Word was made flesh (John 1:14)," not undergoing change, nor converting His own divinity into humanity; - joined together into the one holy perfection and divinity of Himself; - for the Lord Jesus Christ is one and not two, the same God, the same Lord, the same King; and He suffered in the flesh, and rose again and ascended into heaven in the same body, and sits in glory on the right of the Father, about to come in the same body in glory to judge the living and the dead; whose kingdom will have no end; and we believe in the Holy Spirit, who spoke in the Law and proclaimed in the Prophets and descended at the Jordan, speaks in the Apostles and dwelling in the saints; thus do we believe in Him: that the Spirit is Holy, Spirit of God, Spirit perfect, Spirit Paraclete, increate, and is believed to proceed from the Father and to be received from the Son. We believe in one Catholic and Apostolic Church, and in one Baptism of repentance, and in the resurrection of the dead and the just judgement of souls and bodies, and in the kingdom of heaven, and in eternal life. But those who say that there was a time when the Son or the Holy Spirit was not, or was made out of nothing or of another substance or essence, who say the Son of God or the Holy Spirit is liable to change or to becoming different, these people the Catholic and Apostolic Church, your Mother and ours, anathematizes; and again we anathematize those who do not confess the resurrection of the dead, and all heresies which are not consistent with this, the true faith.
-- Baptismal Creed by Epiphanius from about 374 A.D.