The commander suspected he knew who his prisoner was. He had asked the crowd "who he was, and what he had done," but "some cried one thing, some another" (Acts 21:33-34). Paul's Greek drew a question of its own (Acts 21:37). Gill says he asked about Greek "either as wondering to hear him speak Greek, when he thought he had been a Jerusalem Jew, or rather an Egyptian." His question presses Paul to admit he is the Egyptian who had "made an uproar" and led four thousand men into the wilderness. Matthew Henry puts it simply: "See how good men are exposed to ill-will by mistake."

Paul answered plainly: "I am a man which am a Jew of Tarsus, a city in Cilicia, a citizen of no mean city" (Acts 21:39). In the same breath he asked, "I beseech thee, suffer me to speak unto the people." The commander "had given him licence," and Paul stood on the stairs, quieted the crowd with his hand, and spoke to them "in the Hebrew tongue" (Acts 21:40). Paul's answer corrected the mistaken identity and opened the door for Paul's defense.

Barnes says the Egyptian "was probably a Jew who resided in Egypt." He summarizes the Jewish historian Josephus: this man came to Jerusalem claiming to be a prophet, led a crowd to the Mount of Olives, and promised to show them the city walls falling down. Felix, the Roman governor, attacked with soldiers, killing 400 and taking 200 alive, but the Egyptian himself escaped. Josephus elsewhere gives 30,000 followers, but Barnes judges "it is more probable that the number was only 4,000 than that it was 30,000."

The KJV word "murderers" translates sikarioi, the Sicarii or "assassins" (as the ESV has it). Gill explains they were "so called from the little swords which they carried under their clothes," and Barnes traces the word to the Latin sica, a short sword or crooked knife that could be easily concealed under the garment. The commander's soldiers were stationed, Barnes notes, in the tower of Antonia, which he places on the north of the temple; on Acts 21:35 he quotes Josephus that it stood at the corner of the temple's west and north cloisters.

This question belongs to a chapter where almost everyone misreads Paul. The Jews from Asia wrongly "supposed" he had brought a Greek into the temple (Acts 21:29). The crowd shouted different charges (Acts 21:34). Now the Roman officer takes him for a wanted rebel. Paul was none of these things.

Yet God used even the commander's mistake. His question led to Paul's answer, and Paul's answer led to permission to speak to the very crowd that wanted him dead (Acts 21:39-40). Matthew Henry observes that under "such an invidious suspicion, that he was that Egyptian, he kept his temper." A calm, truthful reply turned a false accusation into an open door for testimony (Acts 22:1-21).