Why did Paul endure imprisonment, beatings, shipwreck, and hardship?

Paul endured imprisonment, beatings, shipwreck, cold, heat, and nakedness not to please or serve men, but because he was the bond slave of Jesus Christ. He sought to please God rather than men, recognizing that one cannot serve both, so his suffering flowed from devotion to Christ.

Les teaches that Paul's motivation was not human approval or salary. Paul asked whether he persuaded men or God, and he did not have to be beholden to anybody, even sewing tents when he needed money. Since pleasing men would prevent him from being Christ's servant, he could not serve both God and mammon. His imprisonment, beatings, shipwreck, cold, heat, and nakedness were not for serving men but because he was the bond slave of Jesus Christ. Les connects this to Ephesians chapter 3, verse 1, as the whole motivation of the apostle.

2 Corinthians 11

Did Paul have to suffer even though he wrote 'If God be for us, who can be against us'?

Yes. Paul, the same apostle who wrote "If God be for us, who can be against us," still had to suffer greatly for the Gospel. The context points to 2 Corinthians 11, where he recounts receiving thirty-nine licks five times from the Jews, showing that this promise does not mean believers are exempt from hardship.