The Theology of Arithmetic

...progression toward number, but it is not quite so direct because of its primordial nature. The Triad the number three causes the power of the Monad the number one to proceed into actualized activity and extension. We say "this" original: tode to signify the Monad; we say "either" original: hekateron for the Dyad the number two; but we say "each" original: hekaston for the Triad. Because of this, we use the Triad to express abundance, saying thrice ten-thousand original: tris murioi instead of "many times many," and we use the term thrice-blessed original: trisolbioi. For the same reason, we are accustomed to performing the ritual invocations of the dead three times.

Furthermore, every substance that undergoes a natural progression possesses three limits: a beginning, a peak, and an end original: archē, akmē, teleutē; 16 these are like the boundaries and the middle. It also possesses intervals, such as growth and decay, so that the nature of the Dyad and the concept of "either of two" is revealed within the Triad of limits.

The Triad is also called Good Counsel original: euboulia and Prudence original: phronēsis, since people use it to correct the present, foresee the future, and gain experience from what has already happened in the past. Prudence, then, is a kind of overseer of the three parts of time; consequently, knowledge itself follows the nature of the Triad. They also call the Triad Piety original: eusebeia; hence the name "Triad" was derived from the word to tremble original: trein; a Greek pun suggesting that religious awe or "trembling" before the divine is linked to the number three, meaning to be fearful and reverent.

The number three is called the first "odd" number and is described by some as perfect original: teleios, because it is the first to signify "the whole" or "the all" by having a beginning, a middle, and an end. To honor extraordinary things, people name them "thrice-prosperous" or "thrice-blessed"; likewise, prayers and libations are performed three times. It is the image of a surface and the first of its kind, taking on substance in triangles. There are three types of triangles: equilateral, isosceles, and scalene. Furthermore, there are three types of rectilinear angles: acute, obtuse, and right. Time, too, has three parts. Among the virtues, they likened the Triad to Moderation original: sōphrosunē; also translated as temperance or self-control; for moderation is a symmetry existing between the states of excess and deficiency. Moreover, the Triad—by combining the Monad, the Dyad, and itself—produces the number six 1 + 2 + 3 = 6, which is the first "perfect number" a number equal to the sum of its divisors.