" Perhaps the most likely answer is that, in the Bible, six is the number for human beings. People were created on the sixth day, and they are to work six of seven days. A Hebrew could not be a slave for more than six years. God’s number, on the other hand, is seven. He created seven days in a week. There are seven colors in the visible spectrum and seven notes in a musical scale. Biblically, there are seven feasts of Jehovah (Leviticus 23); seven sayings of Jesus from the cross; and seven “secrets” in the Kingdom parables (Matthew 13). At the fall of Jericho, seven priests marched in front of the army bearing seven trumpets of rams’ horns, and on the seventh day they marched around the city seven times (Joshua 6). "

― David Jeremiah , Agents of the Apocalypse: A Riveting Look at the Key Players of the End Times