Here are a few things I found:
Matthew 3:13 to 4:11, and Parallels - from Machen
Among those who came to be baptized was Jesus of Nazareth. Matt. 3:13–15, and parallels. Jesus did not need to be baptized for his own sake, for he had no sin to be washed away. But his baptism was part of what he was doing for his people. Just as on the cross he received the punishment of sin, though there was no sin of his own, so in his baptism, he represented the sinful people whom he came to save.
When Jesus had been baptized, there was a wonderful event which was perceived not only by him but also by John the Baptist. Matt. 3:16, 17, and parallels. The Holy Spirit descended upon him in the form of a dove, and there was a voice from heaven which said, “This is my beloved Son, in whom I am well pleased.” This event marks the beginning of Jesus’ public ministry as Messiah. He had been the Messiah already, and he had already possessed the Holy Spirit; but now the power of the Spirit impelled him to come forward definitely as the promised One.
Machen, J. G. (1921). Section II: The Life of Christ and the Development of the Church in Apostolic Times and in Post Apostolic Times. In Teaching the Teacher: A First Book in Teacher Training (p. 63). Philadelphia: Westminster Press.
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THE CONFIRMATION OF HIS MESSAGE (Mark 1:9–11)
Verse 9 says, “At that time Jesus came from Nazareth in Galilee and was baptized by John in the Jordan.” Why was Jesus baptized? That is a good question. In fact, Matthew says John asked it: “But John tried to deter him, saying, ‘I need to be baptized by you, and do you come to me?’ Jesus replied, ‘Let it be so now; it is proper for us to do this to fulfill all righteousness.’ Then John consented” (Matthew 3:14, 15). Because Jesus was sinless, he needed no baptism of repentance. But in his baptism he associated himself with us sinners and placed himself among the guilty—not for his own salvation but for ours—not for his guilt but for ours—not because he feared the wrath to come, but to save us from it. His baptism meant the Cross!
My song shall be of Jesus,
The precious lamb of God,
Who gave himself my ransom,
And bought me with his blood.
See and hear the beauty of the moment: “As Jesus was coming up out of the water, he saw heaven being torn open and the Spirit descending on him like a dove. And a voice came from heaven: ‘You are my son, whom I love; with you I am well pleased’” (vv 10, 11). What did Jesus see? Literally, he saw the heavens tearing apart. Then he saw the Holy Spirit in the form of a dove descending into him, as the Spirit publicly entered Jesus for full empowerment for ministry. Jesus also saw the divine poetry, for this same Spirit brooded over the waters at the beginnning of creation (Genesis 1:2).
What did Jesus hear? “You are my Son, whom I love; with you I am well pleased.” God was pleased with his Son’s commitment to be the humble Servant-Savior who would atone for the sins of the whole world (see Isaiah 53:11).
Hughes, R. K. (1989). Mark: Jesus, servant and savior (Vol. 1, pp. 24–25). Westchester, IL: Crossway Books.
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Links:
Why was Jesus baptized? from Got Questions
Why Was Jesus Baptized? by John Piper