The same HOLY SPIRIT that was essential for the earthly work of Christ is necessary for you. Your Salvation experience is based on Christ, the cross, and your confession.
But for the HOLY SPIRIT, you would not have had the Divine experience planned by your Father in Heaven. You would not have access to His wisdom to lead you in life according to God’s Will, thus living daily in Divine Trinity Love, Joy, Peace, and Favor.
BUT, how did you KNOW of your regeneration, your renewal? How did you KNOW your heart had been cleansed? That is the work of the HOLY SPIRIT.
But for the Holy Spirit, you would not have had the Divine experience planned by your Father in Heaven.