The Holy Trinity is perfect. We know that it is revealed only when we come before the Throne of Grace. But, an apparent example of this Trinity was the baptism of the Lord Jesus.
When He had been baptized, Jesus came up immediately from the water; and behold, the heavens were opened to Him, and He saw the Spirit of God descending like a dove and alighting upon Him. And suddenly a voice came from heaven, saying, “This is My beloved Son, in whom I am well pleased.” (Matthew 3:16-17)
The Son, having been baptized in the water... The Holy Spirit, descending upon the Son like a dove... and the Father, identifying from heaven His beloved Jesus.
God the father sacrificed His son whilst being God... God the son having a Spiritual nature sacrificed Himself by not calling on His Spiritual nature... God the Holy Spirit is God — Father and son, who is willing to live in the lives of those who allow Him. Many want to have this miracle inside of them, but they aren't willing to pay the price.
What is the price to pay? The total surrender of YOUR WILL AND 100% OF YOUR ALL for everything God has!
What do you gain with this? SUPERPOWERS! The Holy Spirit inside of you, you become a power person in the Spiritual world. You receive The Spirit to recognize God's voice... He makes you reason, He guides you! Typically, you use these super powers in difficulties and trials.
Why is the Baptism in the Holy Spirit necessary? It's necessary for the survival of faith in this world, every day it's much harder to dwell in it. It's impossible to be a Christian in this world without the seal of the Holy Spirit.
Being a Christian without the baptism of the Holy Spirit is the same thing as hearing about a delicious plate of special food and staying hungry wishing one day being able to eat it. The baptism in the Holy Spirit enables us to personally know the Lord Jesus, it takes us to have personal experiences with God, it guarantees our salvation and it impedes us from being deceived or mislead by our weaknesses, emotions, and feelings by motivating us towards a constant spiritual growth.
The Holy Spirit is the Flame that impedes our faith from going out. Only those who have been sealed by Him have stayed firm.