What would have happened if Peter had not defended Paul's gospel?
Paul's gospel would not have been defended, and Christianity as we know it would have died right then and there and never survived. Though God is sovereign and could have done something else, in the unfolding account Peter's defense that Gentiles could be saved without the law of Moses preserved Christianity.
Les teaches that at Acts chapter 15 Peter finally realized, after all the trials and tribulations the Judaizers had been giving the apostle Paul, that their demand was that Paul's gospel was not sufficient unless Gentiles also became keepers of the law and practitioners of circumcision. But Peter wakes up and comes to the defense of Paul. Les says that had Peter not done this, Paul's gospel, Christianity as we know it, would have died right then and there. Les acknowledges that God is sovereign and could have done something else, but as the unfolding is understood, had it not been for Peter finally coming to his senses and defending the fact that Gentiles could be saved without coming under the law of Moses, Christianity would have never survived. Peter then says in verse 10, since Gentiles are not under the law of Moses, why tempt or test God by putting a yoke upon the neck of the disciples, a yoke which neither the fathers nor the eleven had to chafe under—the demands of the Mosaic law, which was severe.