Acts 23:23
And he called unto him two centurions, saying, Make ready two hundred soldiers to go to Cæsarea, and horsemen threescore and ten, and spearmen two hundred, at the third hour of the night; And he called unto him two centurions, saying, Make ready two hundred soldiers to go to Cæsarea, and horsemen threescore and ten, and spearmen two hundred, at the third hour of the night;
The officer who called the two centurions and gave the order was Lysias, the Roman commander at Jerusalem. The escort he ordered was a large military force of two hundred soldiers, seventy horsemen, and two hundred spearmen. Its mission was to take Paul safely from Jerusalem to Caesarea and deliver him to Governor Felix, placing Paul under Felix's jurisdiction.
The departure was set for the third hour of the night. That hour corresponds to nine in the evening. The escort traveled by night as far as Antipatris, where the horsemen continued on with Paul while the foot soldiers returned to Jerusalem.
The transfer was prompted by unrest in Jerusalem that made Paul's continued presence a danger to the city. It also removed Paul from the danger of a plot against his life. It relieved Lysias himself of danger, since he could be blamed if Paul was killed while in his charge.