What is the unpardonable sin?
The unpardonable sin is rejection of the Father, the Son, and the Holy Spirit—not merely one Person, but all three. In this context, it was Israel's national rejection, after which the Jewish people experienced 2,000 years of suffering and turmoil.
Les explains that this sin was committed when Israel had rejected not only the Father, not only the Son, but now also the Holy Spirit. That national rejection set the nation on a downhill course. For the past 2,000 years, the Jew has gone through suffering and turmoil. Les notes that when this age ends and the Millennial reign begins, Israel will come into God's goodness and grace. After the stoning of Stephen, the next important event is the conversion of Saul of Tarsus. Then Peter fades from the book of Acts, the Gentiles make an ascendancy, and the Body of Christ comes in, showing the transitional aspect of Acts.