Passage 6.20.3
ἐν μὲν δὴ τῷ ἔμπροσθεν τοῦ ναοῦ---διπλοῦς γὰρ δὴ πεποίηται---τῆς τε Εἰλειθυίας βωμὸς καὶ ἔσοδος ἐς αὐτό ἐστιν ἀνθρώποις· ἐν δὲ τῷ ἐντὸς ὁ Σωσίπολις ἔχει τιμάς, καὶ ἐς αὐτὸ ἔσοδος οὐκ ἔστι πλὴν τῇ θεραπευούσῃ τὸν θεὸν ἐπὶ τὴν κεφαλὴν καὶ τὸ πρόσωπον ἐφειλκυσμένῃ ὕφος λευκόν· παρθένοι δὲ ἐν τῷ τῆς Εἰλειθυίας ὑπομένουσαι καὶ γυναῖκες ὕμνον ᾄδουσι, καθαγίζους α ι δὲ καὶ θυμιάματα παντοῖα αὐτῷ ἐπισπένδειν οὐ νομίζουσιν οἶνον. καὶ ὅρκος παρὰ τῷ Σωσιπόλιδι ἐπὶ μεγίστοις καθέστηκεν.
In the front part of the temple—for it has indeed been constructed in two sections—there is an altar dedicated to Eileithyia and an entrance accessible to everyone. In the inner area, Sosipolis receives honors, and entry there is permitted to no one except the woman serving the god, who must cover her head and face with a white veil. Maidens and married women wait inside the precinct of Eileithyia and sing hymns; although they perform sacred rites and burn many kinds of incense, they consider it improper to pour wine as an offering to him. Furthermore, they hold that swearing an oath by Sosipolis is reserved for the gravest matters.