Jesus said,
….Verily, I say unto thee, except a man be born of the water and the SPIRIT, he cannot enter into the Kingdom of God.
John 3:5
Baptism of the Holy Spirit means baptism into Christ. This is the new birth. The word of God and the Holy Spirit are the two agents of salvation.
Paul says;
For by one Spirit are we all baptised into one body, whether we be Jews or Gentiles, whether we be bond or free, and have been all made to drink into one Spirit.
1 Corinthians 12:13.
Again, he says;
Not by works of righteousness, which we have done, but according to his mercy, he saved us by washing of regeneration and renewal of the Holy Ghost.
Titus 3:5.
The Holy Ghost immerses us into Christ. There can be no new birth without the Holy Ghost.