What made it possible for God to reveal the mystery that had been hidden?
The accomplished price of redemption, the completed work of the cross, and the power of His resurrection made it possible. Because these were done, God could pour out the revealed truth—the mystery kept secret since before creation—now given through the Apostle Paul for the Church.
Les explains that the mystery was kept secret in the mind of God since before anything was created, which is why Jesus and Peter could not preach it. However, because the price of redemption was paid, the work of the cross was finished, and the power of His resurrection was demonstrated, God could now pour out the whole package of revealed truth on the human race. This revealed truth comes from the pen of the Apostle Paul and contains all the truth the Church needs today. Les notes that while we should not throw away the rest of the Bible, spending more time in Paul's epistles would bring about change.
Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began,
But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith: