Where did the idea of the hypostatic union of Jesus, that He is both fully human except for sin and fully divine, come from: the Gospels or other New Testament Scripture, an interpretation of the Hebrew Bible, oral tradition, the Church Fathers, or all of the above?
JOHN 10:30, 38
So I think its all of the above apart from just “oral tradition”
Jesus revealed that He and the Father were one. This, as all other aspects of Divine Revelation, was first transmitted orally by the Apostles and Disciples. Toward the end of the first century, this tradition began to be written down in what we now call the New Testament. This Tradition of teaching continued to be handed on orally at the same time and it has always been the oral teaching which is most complete. The Catholic Church was appointed by Christ to safeguard the Tradition as transmitted orally and also what was recorded in both the New and Old Testaments. There is no direct Revelation of the Hypostatic Union in the Old Testament, though one can find hints of it.
It became refined in its understanding thru the first centuries. Christians knew it was the son of God and they knew he was man, but some were uncertain just how man/God was put together or to be understood. The church knew from the beginning, but to define in it in detail was done as a process of rejecting errors.
For instance, some started to think that God inhibited man something like a robot. Or that he was really God that just took on the appearance of man. Or that Jesus was a man but the holiest man to live. There were all sorts of ideas of man/God, until the church put together a real definition of what man/God meant.
And then eventually, thru the councils, the hypostatic union, that is the name, was born.
This is something which frequently happens to our doctrine. When it comes under scrutiny, then the church steps in to define what that particular doctrine entails. And it usually dosen’t define these things until a question or problem arises about the truth and understanding of a doctrine.
“There is one Lord, there is one faith, there is one Father of us all, and through his Son, who came to save us, there is one God living in us all.” (hymn)
Of course these OT verses are understood differently in the Jewish dispensation. i.e. the royal “we” “us”.
Gen. 1:26- God says Let “us” make man in our image. God is of one essence, but three persons.
Gen. 3:22- God says man has become like one of “us”. The plural form is again used in referring to the persons of God.
Ex. 20:2-3 - I am the LORD your God [Elohim], …You shall have no other gods [Elohim] before Me.
Isa. 9:6 – The Father is God. He will have a Son(Jesus Christ) and a Counselor(Holy Spirit).
Isa. 48:16 – In the Old Testament, the nature of God is expressed as three persons in one God.
Jn. 1:1 – The Word is God. The Word is another name for Jesus Christ. This affirms Jesus is God.
Acts. 5:3-4,9 – The Holy Spirit is God. Peter says Ananias lied to the Holy Spirit…not to men, but to God (the Holy Spirit).
1Jn. 5:7 – In the New Testament, the nature of God is expressed as three persons in one God. This is disputed as being a genuine verse, but some early Greek fathers quote it in their commentary.
Tradition & Fathers
" Having first said all these things, baptize into the name of the Father, and of the Son, and of the Holy Spirit…”
Didache 7:1 (~90 AD)
"… having learned that He[Jesus] is the Son of the true God Himself, and holding Him in the second place, and the prophetic Spirit in the third, we will prove”
St. Justin Martyr, First Apology (110-165 AD).
"Wherefore also I praise Thee for all things, I bless Thee, I glorify Thee, along with the everlasting and heavenly Jesus Christ, Thy beloved Son, with whom, to Thee, and the Holy Ghost, be glory both now and to all coming ages. Amen.”
Martyrdom of Polycarp (157 AD).
" For with Him were always present the Word and Wisdom, the Son and the Spirit, by whom and in whom, freely and spontaneously, He made all things, to whom also He speaks, saying, ‘Let Us make man after Our image and likeness;’ He taking from Himself the substance of the creatures [formed], and the pattern of things made, and the type of all the adornments in the world.”
St. Irenaeus of Lyons, Against Heresies (180 AD)
I think for the hypostatic union, we know that He was God. We also know that he was born of a human Virgin where he took on flesh and became Man. So these two natures became unified as part of the Incarnation.
Ex. 3:14 - In the Old Testament, God reveals His name as “I AM who AM”.
Jn. 8:24,58 - In the New Testament, Jesus says of Himself, “Before Abraham was, I AM”.
Lk. 1:31-32 - The angel of the Lord proclaims Jesus as Son of the Most High.
Mt. 2:2,11;8:2;14:33;28:9;28:17;Lk. 24:52;Jn. 9:38 – Jesus allows Jews to worship Him. Only God can be worshipped.
Mt. 9:2;Mk. 2:5;Lk. 5:20;7:48 – Jesus forgives sins. Only God can forgive sins.
Mt. 4:7;Lk. 4:12 – Jesus tells Satan, “you shall not tempt the Lord your God” in reference to Himself.
Mt. 12:8;Mk. 2:28;Lk. 6:5 - Jesus says that He is “Lord of the Sabbath.” He is the Lawgiver. He is God.
Mt. 26:63-64;Mk. 14:61-62;Lk. 22:70;Jn. 10:30 - Jesus claims to be the Son of God.
Jn. 1:1;Rev. 1:8;22:12-13 - John says the Word and God are one. Jesus Christ is the Word; the Alpha and Omega.
Jn. 20:28 - St. Thomas addresses Jesus as “My Lord and my God!”.
Tradition & Fathers
“We have also as a Physician the Lord our God, Jesus the Christ, the only-begotten Son and Word, before time began, but who afterwards became also man, of Mary the virgin.”
St. Ignatius of Antioch, To the Ephesians (A.D. 110)
“For if you had understood what has been written by the prophets, you would not have denied that He was God, Son of the only, unbegotten, unutterable God.”
St. Justin Martyr, Dialogue with Trypho (A.D. 155)
*“But nothing exists, the cause of whose existence is not supplied by God. Nothing, then, is hated by God, nor yet by the Word. For both are one–that is, God.” *
St. Clement of Alexandria, The Instructor (A.D. 202)
Since any doctrinal Catholic truth such as your question has always been, and has not been in its reality thought up, but rather the understanding of it has developed and been articulated as time has gone on, then the clearer way to ask such questions is to ask how such truth developed and has been explained by the Church. It has been the Church’s job, guided by the Holy Spirit, to put such divine mysteries into human language so that those truths can be understood to a certain degree. As time went by and the Church grew, there was not only more questions being asked in search for understanding, but also more attacks against the Church to bring disunity and confusion, and that brought the need for creeds and definitions by the Church to enlighten and preserve correct doctrine.
I would say that the hypostatic union finds its beginnings in a midrash from the Gospel of John, chapter 1:
I would say that this quote from your above citation explains it best:
**The Logos of the Jews
In dualistic circles of thought, where the tendency was increasingly to
represent the Deity as the Absolute in order to free Him from all association
with matter, the Reason of God, tending toward, but not yet
properly having become, a separate personality, that phase of God which
connected God’s otherwise Absolute nature with the world, . . . the]
Logos then in all circles but the Stoic . . . was a link of some kind which
connected a transcendent Absolute with the world and humanity. The
Logos came into general popularity because of the wide-spread desire to
conceive of God as transcendent and yet immanent at the same time**