27 No one can doubt that we have taken the course of true reverence and of sound doctrine when, after proving from Law and Prophets first that Christ is the Son of God, and next that He is true God, and this without breach of the mysterious unity, we proceed to support the Law and the Prophets by the evidence of the Gospels, and prove from them also that He is the Son of God and Himself very God. It is the easiest of tasks, after demonstrating His right to the Name of Son, to show that the Name truly describes His relation to the Father; though indeed universal usage regards the granting of the name of son as convincing evidence of sonship.
But, to leave no loophole for the trickery and deceit of these traducers of the true birth of God the Only-begotten, we have used His true Godhead as evidence of His true Sonship; to show that He Who (as is confessed by all) bears the Name of Son of God is actually God, we have adduced His Name, His birth, His nature, His power, His assertions. We have proved that His Name is an accurate description of Himself, that the title of Son is an evidence of birth, that in His birth He retained His Divine Nature, and with His nature His power, and that that power manifested itself in conscious and deliberate self-revelation.
I have set down the Gospel proofs of each several point, showing how His self-revelation displays His power, how His power reveals His nature, how His nature is His by birthright, and from His birth comes His title to the name of Son. Thus every whisper of blasphemy is silenced, for the Lord Jesus Christ Himself by the witness of His own mouth has taught us that He is, as His Name, His birth, His nature, His power declare, in the true sense of Deity, very God of very God.
Source: On the Trinity (New Advent)