Actually, the NT quotes the prophecy of Isaiah in a different place. Note the pair:
The Prophecy
Isa 42:1-4 - “Here is My Servant, whom I uphold, My Chosen One, in
whom My soul delights. I will put My Spirit on Him, and He will bring
justice to the nations. He will not cry out or raise His voice, nor
make His voice heard in the streets. A bruised reed He will not break
and a smoldering wick He will not extinguish; He will faithfully bring
forth justice. He will not grow weak or discouraged before He has
established justice on the earth. In His law the islands will put
their hope.”
The Fulfillment
Matt 12:15-21 - Large crowds followed Him, and He healed them all,
warning them not to make Him known. This was to fulfill what was
spoken through the prophet Isaiah: “Here is My Servant, whom I have
chosen, My beloved, in whom My soul delights. I will put My Spirit on
Him, and He will proclaim justice to the nations. He will not quarrel
or cry out; no one will hear His voice in the streets. A bruised reed
He will not break, and a smoldering wick He will not extinguish, till
He leads justice to victory. In His name the nations will put their
hope.”
Note that Matthew does not say that Isaiah's prophecy was fulfilled at Jesus' baptism, despite his frequent use of OT prophecies, although the language certainly suggests it.
However, Matthew does say that the incident in Matt 12 did fulfill Isaiah's prophecy. Note the way Matthew sets this out in point form:
This was to fulfill what was spoken through the prophet Isaiah: “Here is My Servant,
- whom I have chosen,
- My beloved,
- in whom My soul delights.
- I will put My Spirit on Him,
- and He will proclaim justice to the nations.
- He will not quarrel or cry out; no one will hear His voice in the streets.
- A bruised reed He will not break, and a smoldering wick He will not extinguish, till He leads justice to victory.
- In His name the nations will put their hope.”
Here the placing of the Spirit of God on Jesus is parallel to the other seven attributes of Jesus' ministry suggesting that Jesus worked in parallel with God, at His direction which is consistent with Jesus' submission to the Father, John 5:19, 10:29, 14:28, Matt 26:39, 28:19. Again, this is perfect agreement with the great "kenosis" passage of Phil 2:5-8 - Jesus humbled Himself and became obedient.
Jesus did this voluntarily according to this same passage. he did not have to do it but voluntarily did so to set us an example of how to live, 1 John 2:5, 6.
That is, because Jesus lived by the Spirit, so must we:
Rom 8:4-9 - [we] do not walk according to the flesh but according to the Spirit.
5 Those who live according to the flesh set their minds on the things of the flesh; but those who live according to the Spirit set
their minds on the things of the Spirit. 6 The mind of the flesh
is death, but the mind of the Spirit is life and peace, 7 because
the mind of the flesh is hostile to God: It does not submit to God’s
law, nor can it do so. 8 Those controlled by the flesh cannot
please God.
9 You, however, are controlled not by the flesh, but by the Spirit, if the Spirit of God lives in you. And if anyone does not have
the Spirit of Christ, he does not belong to Christ.