Note 7 at Acts 21:38: Josephus wrote of this incident which the chief captain is referring to. He said an Egyptian who's name was not known, led an attack on Jerusalem with 30,000 men. He had caused them to believe that if they would help him attack the Romans that the walls of Jerusalem would fall down flat. The Romans defeated this group killing 400 and taking 200 prisoners. The Egyptian escaped and was never found.

Although Josephus spoke of this Egyptian leading 30,000 men and Luke records the chief captain as mentioning only 4,000, most scholars consider this an error on some scribes part in copying Josephus' work. The Greek delta for 4 and the lambda for 30 are very similar. Also the casualties reflect an army the size of 4,000 more closely than an army of 30,000.