The action taken by those who know God is their reaction to the anti-God trends which they see operating around them. While their God is being defied and disregarded, they cannot rest. They feel they must do something; the dishonor due to God’s name goads them into action. This is exactly what we see happening in the narrative chapters of Daniel, where we are told of the exploits of Daniel and his three friends.
John Calvin once explained to a friend why he engaged in controversies. “Even a dog barks,” he wrote, “when his master is attacked: how could I be silent when the honor of my Lord is assailed?” Indeed, how can a servant of Christ remain faithful to his Master when the gospel of Christ is under siege? Paul would not sit still when the gospel was being threatened by the conduct of his friends and colleagues, going so far as to oppose the respected Apostle Peter to his face. Paul had to take action. Why? Because Peter’s man-fearing duplicity (which was leading others astray with him, including “even Barnabas”) “was not in step with the truth of the gospel.”
Paul risked friendship, apostolic unity, reputation, and respect from his peers in order to stand for Jesus Christ.