God, With, Us: Incarnation in Three Soundbites

I. Incarnation summed up: "Jesus is Lord."
The apostles' collective discovery process yields the conviction that Jesus is Lord, implying that

1. Jesus is fully human.
2. Jesus is fully divine.
3. Jesus is one person: The human Jesus is the divine Jesus.

'Heresies' are inferences that the early church has broadly rejected for compromising one or more of these affirmations.

II. Jesus' Human Nature
Jesus' humanity is taken for granted in the New Testament.
Yet the NT draws theological conclusions from Jesus' humanity:

Romans 5:12-21: Jesus is a righteous 'last Adam' redeeming sinners.
1 Corinthians 15: Jesus' resurrection is paradigmatic for humanity's eternity.
Hebrews 2:14-18, 4:15-16, etc.: Jesus can intercede for fellow humans.

III. Jesus' Divine Nature
(Why are the signs so subtle in the New Testament?)

Surface indicators: One-line 'prooftexts' assert it:

Raymond E. Brown lists John 20:28, Rom 9:5, Heb 1:8, 1 John 5:20, Titus 2:13 + 2 Peter 1:1, John 1:1, John 1:18, John 8:58.
Why so few?

Deeper indicators: Narrative roles and acts of Jesus include

... a role in creation: 1 Cor 8:6, Col 1:16, Heb 1:2, John 1:2-3.
... sovereignty over creation: calming the storm (cf. Ps 107:23-31), lordship over the sabbath, walking on water, feeding miracles.
... forgiving and judging: Healing the paralytic, sheep and goats, 2 Cor 5:10.
... the primary role in salvation: Luke 19:10, "savior" title, healings/exorcisms.
... special relationships with the One who sent him and with the Holy Spirit (so Trinity).

Deepest indicators: Pervasive worship practices reflect the church's given relationship with Jesus (Rev 1:12-18).
His title 'Lord' (Hebrew adonai, and later Greek kurios) stands in for 'YHWH'

in, e.g., Phil 2:5-11 (after Isa 45:22-23) and 1 Cor 16:22 (marana tha).

The Councils of Nicea, 325 and Constantinople, 381 respect these convictions by affirming both humanity and divinity.

IV. Unity
How are they one? Ancient orthodox schools of thought saw 'hypostatic union'

as Alexandrian 'Word-flesh' Christology (cf. John 1)
(vulnerable to compromising Jesus' true humanity)
or Antiochian 'Word-man' Christology (cf. Mark 1)
(vulnerable to compromising Jesus' unity or divinity).

Chalcedon clarified it in 451 (after Ephesu basically did too in 431):

Christ is "one person in two natures without confusion, change, division, or separation."

Result: Communication of attributes (communicatio idiomata).

Each nature influences (without compromising) the other.

Chalcedonian orthodoxy implies divine humanity (Athanasius) and human divinity (Luther, Barth).

(John of Damascus' analogy: red-hot iron.)

My alternative interpretation sees a "concurrence of relations":

The relationships constituting divine personhood and human personhood concur in this one person.

Either way, incarnation grounds doctrines of salvation (e.g., Anselm's satisfaction theory).