The division of the day into hours was probably borrowed by the Jews from the Babylonians, who were careful astronomers and at a very early time invented the system of hours, minutes, and seconds that we still use. In the O.T. no divisions of the day are mentioned beyond morning, noon, and evening. The night was divided into three watches, afterwards increased to four. In the only passages in O.T. in which hour occurs (Dan. 3: 6; Dan. 4: 19, 33; Dan. 5: 5), it denotes an indefinite length of time. In the N.T. period the use of the hour was well established. The hours of the day were counted from sunrise, the hours of the night from sunset, and they varied in length at different seasons of the year.