Passage 7.26.7
Ἀσκληπιοῦ δὲ ἀγάλματα ὀρθά ἐστιν ἐν ναῷ καὶ Σαράπιδος ἑτέρωθι καὶ Ἴσιδος, λίθου καὶ ταῦτα Πεντελησίου. τὴν δὲ Οὐρανίαν σέβουσι μὲν τὰ μάλιστα, ἐσελθεῖν δὲ ἐς τὸ ἱερὸν οὐκ ἔστιν ἀνθρώποις. θεοῦ δὲ ἣν Συρίαν ἐπονομάζουσιν, ἐς ταύτης τὸ ἱερὸν ἐσίασιν ἐν ἡμέραις ῥηταῖς, ἄλλα τε ὅσα νομίζουσι προκαθαριεύσαντες καὶ ἐς τὴν δίαιταν.
There are upright statues of Asclepius in the temple, as well as statues of Serapis and Isis in another place, all made of Pentelic marble. They particularly venerate Urania, but no human being may enter her sanctuary. As for the goddess whom they call the Syrian goddess, people enter her sanctuary on appointed days, but only after purifying themselves according to prescribed rites, including practices concerning their diet.