"The cross without the Holy Spirit is absolutely ineffective. Only the Holy Spirit can take what the cross has accomplished and make believers experience it. If we hear the truth of the cross but do not allow Him to work this truth into our lives, then we know nothing but a theory and an ideal" Romans 8:9-13.
It is The Holy Spirit who translates the cross into an experience. He gives live to God's purposes, even, scriptures. He is the One that translates the letter written in the Bible into an experience. He reveals the work of the cross and the love of God to mankind.
"The love of God is shed in our hearts by the Holy Ghost" (Romans 5:5).
He shows the world that their refusal to believe in Jesus is their basic sin and that righteousness comes from above where Jesus is with the Father. He also shows that judgment takes place as the ruler of this godless world is brought to trial and convicted.