Definition (house style)
The baptism of Jesus (Luke 3:21-22; Matt. 3:13-17; Mark 1:9-11; John 1:32-34) is the event in which Jesus was baptised by John in the Jordan, the Holy Spirit descended upon him as a dove, and a voice from heaven declared: “You are my beloved Son; with you I am well pleased.” On apokatastasis.wiki the baptism is christologically significant as the inauguration of the threefold office: the anointing of the Spirit constitutes Christ as prophet (in the line of Moses, Deut. 18:15), priest (after the order of Melchizedek, Ps. 110:4), and king (Son of David, 2 Sam. 7:12-14).
The baptism also marks the beginning of Jesus’ public ongoing kenosis: after thirty years of hidden life in Nazareth, this moment inaugurates the public redemptive work.
Usage per author
Noordzij
Noordzij identifies the baptism as the moment of anointing to the full threefold office and connects the heavenly declaration to the prophetic, priestly, and royal dimensions of Jesus’ calling:
“Then the Father anointed Him as true King and High Priest and declared: ‘You are My Son, the beloved, in whom I am well pleased’ (Luke 3:21-22). What riches! King, High Priest, Son of the living God!”
[Noordzij, Moses and the Way to Sonship, §48 — translated from Dutch]
The prophetic office Noordzij connects to the fulfilment of the Mosaic prophecy: the baptism inaugurates the ministry of the prophet “like Moses” who led Israel to freedom, but now as the Prophet who comes from above (John 10:3; 12:32).
Bullinger
Bullinger connects the jubilee opening of Jesus’ ministry — the reading of Luke 4:18-19, immediately following the baptism and temptation — to his jubilee chronology: thirty jubilee years (1,500 years) lead from the Exodus to the moment when Christ proclaimed “the acceptable year of the Lord”:
“Thirty jubilee years bring us from the Exodus to the opening of Christ’s ministry, when He, opening Isa. 61:2, proclaimed ‘the acceptable year of the Lord’ in a sevenfold prophecy (see Luke 4:18-21).”
[Bullinger, Number in Scripture, Part I, ch. I]
The baptism is for Bullinger the chronological and typological pivot: the moment when the 1,500-year jubilee pattern reaches its christological fulfilment.