Today is the feast of St. Ambrose of Milan, Doctor of the Church. He was made bishop of Milan against his will, by popular acclaim; when as governor he went to the Church to make sure that the selection of a new bishop would be orderly, the people started shouting, "Ambrose, bishop!" He fled and locked himself in his house, but it was too late; rumor travels swiftly, and the Emperor, having heard that he had been chosen as bishop, sent him congratulations and selected his replacement as governor, so he didn't have much else he could do. He was a catechumen, so he had to be baptized, confirmed, ordained, and raised to episcopal office all in one week. But having thereby been made a victim of his own extraordinary competence, he handled being bishop with the same intelligence and ability that had made him popular as governor. From his criticism of Arianism in De Fide (Book V, Chapter 11):
But we have sufficiently proved by examples from Scripture that it is a property of the unity of the divine majesty that the Father should abide in the Son, and that the Son should seem to have heard from the Father those things which He speaks. How else can we understand the unity of majesty than by the knowledge that the same deference is paid to the Father and the Son? For what can be better put than the Apostle's saying that the Lord of glory was crucified?
The Son then is the God of glory and the Lord of glory, but glory is not subject to creatures; the Son therefore is not a creature.
The Son is the Image of the Father's Substance; but every creature is unlike that divine Substance, but the Son of the Father is not unlike God; therefore the Son is not a creature.
The Son thought it not robbery to be equal with God; but no creature is equal with God, the Son, however, is equal; therefore the Son is not a creature.
Every creature is changeable; but the Son of God is not changeable; therefore the Son of God is not a creature.
Every creature meets with chance occurrences of good and evil after the powers of its nature, and also feels their passing away; but nothing can pass away from or bring addition to the Son of God in His Godhead; therefore the Son of God is not a creature.
Every work of His God will bring into judgment; but the Son of God is not brought into judgment; for He Himself judges; therefore the Son of God is not a creature.
Lastly, that you may understand the unity, the Saviour in speaking of His sheep says: No man is able to pluck them out of My hand. My Father Which gave them to Me is greater than all, and no man is able to pluck them out of My Father's hand. I and My Father are one.