midnight
Jethro learned that as soon as the inner wall was completed the Egyptians had ceased altogether to keep watch at the gates of the city walls , but that they had for a long time kept a vigilant guard at the gate leading to their quarters through the new wall . For the last year , however , owing to the absence of any spirit of revolt among the Rebu , and to their confidence in the friendship of the king , they had greatly relaxed their vigilance . By nine o'clock all was quiet in the town . Jethro sent out a messenger by the road by which Amuba 's force would approach , to tell him that the city walls were all unguarded , and that he had better enter by the gate half an hour before midnight , instead of waiting until he heard the signal for attack . He could then move his men up close to the Egyptian wall so as to attack that gate when the signal was given , otherwise the Egyptians would be put on their guard by the sound of fighting at the palace before he could arrive at their gate . At the time he had named Jethro went to the gate by which Amuba was to enter , and soon heard a faint confused noise , and a minute or two later a dark mass of men were at the path at the gate . They were headed by Amuba .