Why did Paul say he would have no opposition if he preached circumcision?

Paul said preaching circumcision would bring no opposition because the Judaizers’ main reason for hating and fighting him was his refusal to circumcise Gentile believers. If he preached their message, he would have clear sailing; if he stopped opposing legalism and the Law, the offense of the cross would cease.

Les teaches that Paul’s opponents, the Judaizers from Jerusalem, were persecuting him mainly because he would not give in to circumcising Gentile believers. Paul says that if he preached what they preached, he would have clear sailing and no opposition. He asks, if he preached circumcision, why did he still suffer persecution? If he stopped preaching against legalism and the Law, the offense of the cross would be brought to an end. All Paul had to do was succumb to the pressure and say he would preach circumcision and law keeping, and they would get off his back. But God would not have been satisfied, though the world would have been, and the Church would have died a natural death. Paul never backed off or gave in to the Judaizers; he stood his ground so the truth of the Gospel might continue with the Gentiles, and he suffered persecution every day of his life.

Galatians 5:11

And I, brethren, if I yet preach circumcision, why do I yet suffer persecution? then is the offence of the cross ceased.

Why would Paul have had clear sailing if he preached what the Judaizers preached?

Paul would have had clear sailing because the Judaizers’ opposition and persecution centered on his refusal to require Gentile circumcision and law keeping. If he had preached their message of circumcision and legalism, he would have avoided their hostility and suffering, but God would not have been satisfied and the Gospel would have been compromised.