Why is six considered the number of man in the Bible?
Six is the number of man because the six days of creation prepared everything for the appearance of mankind. Scripture applies six to man throughout creation and the whole biblical record, while the seventh day is God's rest. It marks man's period, contrasted with God's rest.
Les explains that when you come to the seven days back in Genesis, they are broken down so that six days prepared all of creation for the appearance of man. Therefore six has always been the number of man all the way through creation and all the way up through Scripture. Six days and God got everything ready for mankind, but then comes the seventh day, the day of God's rest. Les connects this with the principle in 2 Peter 3:8 that one day is with the Lord as a thousand years and a thousand years as one day. He also points out that for 6,000 years man has pretty much run the show, at least he thinks he does, but there is that 7,000th years left.