The Meaning of Numbers: The Number 4
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.
Interestingly, the Hebrew word for 'seasons' in Genesis 1:14 is moed (Strong's Concordance #H4150), which literally translated is "appointed times" (divine appointments) in reference to God's festivals. This is the earliest known allusion to what would later be called the Holy (or Feast) days (periods) of worship, which are seven in number.
The 4th of the Ten Commandments is to remember and keep God's holy Sabbath day (Exodus 20:9 - 11). The Sabbath day is tied directly to the creation week. God himself made the period between Friday sunset and Saturday sunset extra special when he rested on it after bringing everything into existence the previous six days (Genesis 2:1 - 3, Exodus 20:11).
Appearances of the number four
One of the top ten most frequently mentioned women in the Bible, Eve, is only referenced four times (Genesis 3:20, 4:1, 2Corinthians 11:3 and 1Timothy 2:13).
Psalm 107 is the only section or chapter in God's word that contains the exact same phrase four times (Psalm 107:8, 15, 21 and 31).
The apostle Paul was a man familiar with 4 major first century cultures. He was a Roman citizen, he was a Jew who spoke Greek as well as Hebrew, and he was a Christian.