Man is a three fold creature having spirit, mind and body. Likewise every system has a first, middle and a last part, so 3 was considered the first perfect number.
Pythagoras called 3 “the one and the many”. meaning a limited expression of both 1 and 2, and a number of talents because 3 is the creative principle in the Godhead, the number of self-expression.
The 3 is an 8 with the left side open, so 8 makes its own boundaries by organizing its affairs. The 3 is open to scatter its energies.