Day : The Jews reckoned the day from sunset to sunset (Leviticus 23:32). It was originally divided into three parts (Psalm 55:17). "The heat of the day" (1 Samuel 11:11; Nehemiah 7:3) was at our nine o'clock, and "the cool of the day" just before sunset (Genesis 3:8). Before the Captivity the Jews divided the night into three watches,
The division of the day by hours is first mentioned in Daniel 3:6,15; 4:19; 5:5. This mode of reckoning was borrowed from the Chaldeans. The reckoning of twelve hours was from sunrise to sunset, and accordingly the hours were of variable length (John 11:9).
The word "day" sometimes signifies an indefinite time (Genesis 2:4; Isaiah 22:5; Hebrews 3:8, etc.). In Job 3:1 it denotes a birthday, and in Isaiah 2:12, Acts 17:31, and 2 Timothy 1:18, the great day of final judgment.