The number 3 was the basis for the construction of military units in the Bible.
In 2 Samuel 23, there is a story on this very basic unit, the "three warriors" that King David had. In the same
chapter, there is a detailed account of the "thirty chiefs" who went down to join David at the cave of Adulam.
In Judges 7, when Gideon needs to fight the Midianites, he chooses three hundred men.
In 1 Samuel 13, Saul chose three thousand out of Israel to fight the Philistines, who at the same time "mustered to
fight with Israel thirty thousand chariots."
In 2 Samuel 6, "David again gathered all the chosen men of Israel, thirty thousand" to fight the Philistines.
The phiosopher Judaeus of Alexandria (20 BC - 40 AD) said that God created the world in six days because six was a perfect number.
St. Augustine said in The City of God:
"Six is a number perfect in itself, and not because God created the world in six days; rather the contrary is true: God created
the world in six days because this number is perfect, and it would remain perfect, even if the work of the six days did not exist."
The next perfect number is 28. Some Biblical commentators regarded 28 as a basic number of the Supreme Architect, pointing to
28 days of the lunar cycle.