The number 4 derives its meaning from creation. On the fourth day of what is called 'creation week' God completed the material universe. On this day he brought into existence our sun, the moon, and all the stars (Genesis 1:14 - 19). Their purpose was not only to give off light, but also to divide the day from the night on earth, thus becoming a basic demarcation of time. They were also made to be a type of signal that would mark off the days, years and seasons.
In the Bible, the number 6 symbolizes man and human weakness, the evils of Satan and the manifestation of sin. Man was created on the sixth day. Men are appointed 6 days to labor.
Used 735 times (54 times in the book of Revelation alone), the number 7 is the foundation of God's word. If we include with this count how many times 'sevenfold' (6) and 'seventh' (119) is used, our total jumps to 860 references.
The number 8 in the Bible represents a new beginning, meaning a new order or creation, and man's true 'born again' event when he is resurrected from the dead into eternal life.