But an opportunity came when Herod on his birthday gave a banquet for his high officers and military commanders and the leading men of Galilee.

While they were trying to kill him, a report came up to the commander of the Roman cohort that all Jerusalem was in confusion. At once he took along some soldiers and centurions and ran down to them; and when they saw the commander and the soldiers, they stopped beating Paul. Then the commander came up and arrested him, and ordered him to be bound with two chains. He inquired who he was and what he had done.read more.
Some in the crowd shouted one thing, and some another; and as he could not learn the facts because of the uproar, he ordered him to be brought into the barracks.

When the centurion heard this, he went to the commander and told him, saying, "What are you about to do? For this man is a Roman citizen." So the commander came and said to him, "Tell me, are you a Roman citizen?" And he said, "Yes." The commander answered, "I bought this citizenship for a large sum." Paul said, "But I was born a citizen."read more.
So those who were about to examine him withdrew from him immediately; and the commander also was afraid when he realized that Paul was a Roman citizen and that he had put him in chains. But on the next day, wishing to know for certain why he had been accused by the Jews, he released him and ordered the chief priests and all the Council to assemble, and brought Paul down and set him before them.

The dispute became so violent that the commander was afraid Paul would be torn to pieces by them and ordered the troops to go down and take him away from them by force, and bring him into the barracks.

But Felix, having a more exact knowledge about the Way, put them off, saying, "When Lysias the commander comes down, I will decide your case."

No soldier in active service gets entangled in civilian affairs, since his aim is to please the one who enlisted him as a soldier.