When Paul went to Corinth he confesses he shook in his boots or sandals. He writes in 1 Corinthians 2:3, “I came to you in weakness and fear, and with much trembling.” In that state he made sure he stuck to the basics, “Jesus Christ and Him crucified.”
Then he relied on the demonstration of the Spirit’s power. He wanted any who expressed faith to be trusting in the power of God.
He then shared insights into the producing of God’s Word, the Bible. There are three basic steps in the communication of God’s Word. First, there is revelation, verse 10, God revealed by His Spirit what otherwise couldn’t be known.
Then there is inspiration, verse 13, “This is what we speak, not in words taught us by human wisdom but in words taught by the Spirit, expressing spiritual truth in spiritual words.” When a man communicated what God revealed to him he used his own learned vocabulary. Inspiration is the process whereby the Holy Spirit guided chosen men to use the right words within their vocabulary to express accurately what was revealed. It was not dictation, except where you have, “Thus says the Lord!” Men were guided by the Holy Spirit not to say more than what was revealed, nor less. And the right words within their vocabulary were selected so that exactly what God wanted said would be said.
Illumination is when the Holy Spirit helps the one who has trusted in Christ for Salvation to understand the Bible. Man can’t understand God’s Word apart from the illuminating work of the Holy Spirit, verse 14. In fact he will likely consider it foolishness.