Where did Paul's teachings come from?
Paul makes it plain that everything he writes he received from the Lord in glory. So his teachings are still the words of Jesus, now given post-resurrection after Christ finished the work of the cross. This is why adherence to Paul's writings matters, for there the meat of doctrine lies.
Les explains that when you get to the apostle Paul, Paul makes it plain that everything he writes he received from the Lord in glory. So it is still the words of Jesus, but now in the time most appropriate—post-resurrection, after Christ has finished the work of the cross. Les contrasts this with what Jesus said in His earthly ministry before the cross, before He had died, gone to the cross, or shed His blood. Therefore Les stands by his guns that we must adhere to the writings of Paul, because this is where the meat of our doctrine really lies.