And Jesus, when He was baptized, went up straightway
out of the water: and, lo, the heavens were opened unto
Him, and He saw the Spirit of God descending like a dove, and lighting upon Him.
-Matthew 3: 16
And straightway coming up out of the water, He saw the heavens opened, and the Spirit like a dove descending upon Him.
-Mark 1: 10
In fulfilling God's righteous law, Jesus was sprinkled with His own blood at His circumcision. He fully poured out His own sacrificial blood upon the cross at the close of His earthly ministry when He cried out, "It is finished." He was anointed by the Holy Spirit at the beginning of His ministry, after His baptism, when "the Holy Ghost descended in a bodily shape like a dove upon Him" (Luke 3:22a).
Therefore, to perfectly "fulfill all righteousness," the great High Priest had also to be "washed with the consecrating water of sprinkling." A departure from this mode of baptizing at the commencement of Christ's official ministry would have resulted in His not perfectly "fulfilling the righteousness of the law."
As a priest, in an ancient lineage of priests, John the Baptist would have been familiar with all the righteous demands of the law regarding priestly ordination. Immersion had no part in the ceremonial ordinances regarding priesthood. All was done by pouring and sprinkling -also for prophetical and kingly anointings. If John had broken the requirements of God's law regarding Christ's official consecration to His earthly ministry, the approval of God the Holy Spirit as seen resting upon Him, and of God the Father as heard in the voice from heaven saying, "Thou art My beloved Son; in Thee I am well pleased" (Luke 3:22b) would not have taken place.
The sign of the baptism with water by John signified the reality of the baptism of the Holy Spirit from God. Jesus' baptism by the Holy Spirit is portrayed by expressions such as: "The Spirit of God descending like a dove" and' 'lighting upon Him" (Matthew 3:16b); "The Spirit of the Lord God is upon Me; because the LORD hath anointed me" (Isaiah 61:1a and Luke 4:18); and "God anointed Jesus of Nazareth with the Holy Ghost and with power"(Acts 10:38a).
The mode of sprinkling or pouring matches the mode of the Spirit's "anointing" or "descending and lighting upon."