This is all very helpful; thank you! Would you say there is no one behind Jesus, and He is the fountain of deity as well?
I'm trying to imagine Jesus being equal in power and glory from all eternity with the Father, and being the creator and sustainer of all things, yet being called Son. I don't think my mind can grasp the complexity of it, though I believe it whole-heartedly.
Here is a helpful breakdown by William Gouge by way of commenting on Hebrews 3:5-6:
"Sec. 55. Of Christ a Son in reference to God
The first branch of Christ’s excellency wherein he is preferred before Moses, is his dignity, arising from his birthright. This is here set down in the same manner that the inferiority of Moses was, by a particle of resemblance, ὡς υἱὸς, as. Hereof see Sec. 51.
Here this phrase, as a Son, may be taken two ways.
1. By way of resemblance, thus: As in men’s families the son and heir is counted more excellent than any servant, so the Son of God in the house of God. In this sense it is thus fitly translated, ‘as a Son.’
2. By way of eminency, thus, as the true, proper Son of God, more excellent than all mere creatures. In this sense it was thus fitly translated, ‘as the Son.’ Thus it implieth, that it is no usurpation for Christ to be over the house of God; it is his right, as he is the Son of God.
The former sense cometh up to this latter, and infers the same conclusion, that Christ, being the true proper Son of God, must needs be more excellent than Moses, that was but a servant.
By this argument the apostle proved Christ to be more excellent than angels, Chap. 1. Secs. 42, 47.
This title Son, in reference to God, attributed to Christ, affords matter of instruction and direction.
I. Instructions are these,
1. Christ is true God. As a son of man is true man, so the Son of God is true God.
2. Christ is God eternal. Divine generation is an eternal act.
3. Christ is equal with God. The Son is equal with the Father.
4. In Christ God is well-pleased, Mat. 3:17.
5. In Christ we are adopted God’s sons and made heirs, Gal. 4:4–6.
6. In Christ we are made free, John 8:36.
II. Directions are these,
1. Honour Christ as God, John 5:23.
2. Hear him, Mat. 17:5.
3. Believe on Christ, John 3:16.
4. Submit to Christ, Ps. 2:12.
5. Confess Christ, 1 John 4:15.
6. Depart not from Christ, John 6:68, 69.
7. Tread not Christ under foot, Heb. 10:29.
8. Wait for Christ from heaven, 1 Thes. 1:10.
Gouge, W. (1866). A Commentary on the Whole Epistle to the Hebrews (Vol. 1, pp. 224–225). Edinburgh; London; Dublin: James Nichol; J. Nisbet & Co.; G. Herbert."