Was what Jesus said during His earthly ministry spoken to us?
No, what Jesus said during His earthly ministry was spoken to the nation of Israel under the Law. Although applications can be made from it, it was not spoken directly to us. The apostle Paul's writings are Holy Spirit inspired and directed to Gentiles in this age of grace.
Les teaches that many people claim to follow what Jesus said rather than Paul, but Jesus' earthly words were addressed to the nation of Israel under the Law. While we can make applications from them, they were not spoken to us. By contrast, Paul's writings are Holy Spirit inspired and directed to Gentiles in this age of grace. Paul had to defend his apostleship against false teachers who claimed to follow Peter or Jesus.