Commentary on the First and Second Chapters of the Thirtieth Book of the Natural History of Gaius Plinius Secundus

is a marvelous power: for it is an odd number, thus embracing the most perfect pairs, in which Divine majesty rejoices, as the Mantuan Virgil says. For the Pythagoreans used the ternary number in purifications, which Virgil also taught symbolically, when he says:
"The same thrice carried his companions around with a pure shadow."
For it is produced by the same to be efficacious in bindings and sanctifications, as can be conjectured from his own words, where it is said:
"Three colors distinct with a threefold dye I bind for you: and thrice around the altars I lead the image."
And he adds:
"Weave the three colors with three knots, Amaryllis; weave them, and say, 'I weave the bonds of Venus.'"
And it is read concerning Medea:
"And she spoke thrice the words that make for calm sleep, which stop the turbulent sea and the rushing rivers."
The Mages certainly used this effect of the number to bind, loose, and cure illnesses. The quaternary number also is reported to have no small power in these things. For there are those who preferred it to the other powers of numbers: for the Mages call it the fountain of nature: for the more learned testify that human nature consists of four degrees, which they call: To Be, To Live, To Sense, To Understand. They assign these four also to motion: the four corners of the sky: the four elements: the four triplicities in the sky: the four qualities: the four seasons of the year: they also assert that mathematical doctrine consists of four terms, Point, Line, Surface, Depth: furthermore, that all of nature is gathered into four terms, Substance, Quantity, Quality, and Motion. Therefore, the Pythagoreans say that it has the greatest power in mysteries; hence they swear by the quaternary number, as a certain summit upon which faith relies and by which belief can be confirmed: hence the Hebrews accepted the ineffable name of God in four letters: the most learned of the Greeks also call it the Tetragrammaton, that is, four letters