Nine, the Number of Completion

Nine is the last of the single digits and the number of completion and fulfilment, the end of the cycle before the return to unity at ten. It is three times three, the triad raised on itself, and it has a striking arithmetical property that the ancients noticed and that underlies its symbolism of return: any multiple of nine has digits that sum to nine, and adding nine to any number leaves that number's digit-sum unchanged, so nine behaves in digit-reduction as though it were nothing and everything at once, it always comes back to itself. This is why it reads as the number of the whole cycle, of attainment and of the ending that contains all that went before.

Traditions reach for nine to mark completeness: the nine months of gestation, the nine orders of angels, the nine worlds of Norse myth. In modern numerology nine is the number of completion, compassion, idealism and the humanitarian, the wisdom and letting-go of the final digit. That character belongs to the early-twentieth-century American system, though the arithmetical peculiarity of nine that inspires it is real and old.