When the officers went back and reported what Paul and Silas had told them, the magistrates were frightened, especially upon hearing that they had beaten two Roman citizens without due process.
And remember this: When people publicly accuse you and forcefully drag you before the religious leaders and authorities, do not be troubled. Don’t worry about defending yourself or how to answer their accusations.
All of the soldiers who were about to whip Paul backed away, because they were afraid of the consequences for tying up and holding a Roman citizen against his will.