As Paul is making his case to Agrippa and Bernice Festus said with a loud voice:
“Paul, you are out of your mind; your great learning is driving you out of your mind.”
(Acts 26.24b, ESV)
Paul replies, politely (v.25a), that he is speaking both true and rational words. God is a God of clarity, reason, and non-contradiction. For Paul to be speaking the truths of God is almost a guarantee that he is not out of [his] mind.
Paul knew that Agrippa knows about these things and that the truths of Jesus have not been done in a corner. Paul then presents Agrippa with a choice: believe the prophets of Israel to their logical, prophetical, and theological conclusion – Jesus:
“Do you believe the prophets, King Agrippa? I know that you believe.”
Agrippa said to Paul, “In such a short time are you persuading me to become a Christian?”
Paul replied, “I pray to God that whether in a short or a long timenot only you but also all those who are listening to me today could become such as I am, except for these chains.”
(Acts 26.27-29, NET)
Getting straight to the heart, Agrippa knows that to believe in the prophets and what they foretold would persuade [him] to become a Christian. Each and every prophet spoke to the people in their place and at their time, but also spoke ahead to the reality of Jesus’ life, death, and resurrection (John 5.39, Luke 24.27).
The same is true for you and for me. To believe in bits of the Bible is to believe in the whole. To believe that the Bible speaks truth, to affirm that God spoke to people through other people, is to see and believe that they all spoke towards one world-changing, life-saving truth: Jesus.