Passage 8.38.7
ἔστι δὲ ἐπὶ τῇ ἄκρᾳ τῇ ἀνωτάτω τοῦ ὄρους γῆς χῶμα, Διὸς τοῦ Λυκαίου βωμός, καὶ ἡ Πελοπόννησος τὰ πολλά ἐστιν ἀπʼ αὐτοῦ σύνοπτος· πρὸ δὲ τοῦ βωμοῦ κίονες δύο ὡς ἐπὶ ἀνίσχοντα ἑστήκασιν ἥλιον, ἀετοὶ δὲ ἐπʼ αὐτοῖς ἐπίχρυσοι τά γε ἔτι παλαιότερα ἐπεποίηντο. ἐπὶ τούτου τοῦ βωμοῦ τῷ Λυκαίῳ Διὶ θύουσιν ἐν ἀπορρήτῳ· πολυπραγμονῆσαι δὲ οὔ μοι τὰ ἐς τὴν θυσίαν ἡδὺ ἦν, ἐχέτω δὲ ὡς ἔχει καὶ ὡς ἔσχεν ἐξ ἀρχῆς.
On the highest peak of the mountain there is a mound of earth, the altar of Zeus Lycaeus, from where most of the Peloponnese can be seen. In front of the altar stand two columns, positioned toward the rising sun; upon these were originally placed gilded eagles, made in even earlier times. Upon this altar they sacrifice offerings to Zeus Lycaeus in secret. It was not pleasing to me to inquire closely about the details of this sacrifice; let it remain as it is, and as it was from the beginning.