Plutarch, De Iside et Osiride 36 (part 2)

Δία μὲν γὰρ Αἰγύπτιοι τὸ πνεῦμα καλοῦσιν, ᾧ πολέμιον τὸ αὐχμηρὸν καὶ πυρῶδες· τοῦτο δʼ ἥλιος μὲν οὐκ ἔστι, πρὸς δʼ ἥλιον ἔχει τινὰ συγγένειαν· ἡ δʼ ὑγρότης σβεννύουσα τὴν ὑπερβολὴν τῆς ξηρότητος αὔξει καὶ ῥώννυσι τὰς ἀναθυμιάσεις, ὑφʼ ὧν τὸ πνεῦμα τρέφεται καὶ τέθηλεν.

Not only the Nile, but every form of moisture they call simply the effusion of Osiris; and in their holy rites the water jar in honour of the god heads the procession. And by the picture of a rush they represent a king and the southern region of the world, and the rush is interpreted to mean the watering and fructifying of all things, and in its nature it seems to bear some resemblance to the generative member. Moreover, when they celebrate the festival of the Pamylia which, as has been said, is of a phallic nature, they expose and carry about a statue of which the male member is triple; for the god is the Source, and every source, by its fecundity, multiplies what proceeds from it; and for many times we have a habit of saying thrice, as, for example, thrice happy, and Bonds, even thrice as many, unnumbered, unless, indeed, the word triple is used by the early writers in its strict meaning; for the nature of moisture, being the source and origin of all things, created out of itself three primal material substances, Earth, Air, and Fire. In fact, the tale that is annexed to the legend to the effect that Typhon cast the male member of Osiris into the river, and Isis could not find it, but constructed and shaped a replica of it, and ordained that it should be honoured and borne in processions, plainly comes round to this doctrine, that the creative and germinal power of the god, at the very first, acquired moisture as its substance, and through moisture combined with whatever was by nature capable of participating in generation. There is another tale current among the …