Passage 5.13.3
ἔστι δὲ ὁ ξυλεὺς ἐκ τῶν οἰκετῶν τοῦ Διός, ἔργον δὲ αὐτῷ πρόσκειται τὰ ἐς τὰς θυσίας ξύλα τεταγμένου λήμματος καὶ πόλεσι παρέχειν καὶ ἀνδρὶ ἰδιώτῃ· τὰ δὲ λεύκης μόνης ξύλα καὶ ἄλλου δένδρου ἐστὶν οὐδενός· ὃς δʼ ἂν ἢ αὐτῶν Ἠλείων ἢ ξένων τοῦ θυομένου τῷ Πέλοπι ἱερείου φάγῃ τῶν κρεῶν, οὐκ ἔστιν οἱ ἐσελθεῖν παρὰ τὸν Δία. τὸ δὲ αὐτὸ καὶ ἐν τῇ Περγάμῳ τῇ ὑπὲρ ποταμοῦ Καΐκου πεπόνθασιν οἱ τῷ Τηλέφῳ θύοντες· ἔστι γὰρ δὴ οὐδὲ τούτοις ἀναβῆναι πρὸ λουτροῦ παρὰ τὸν Ἀσκληπιόν.
The Woodman is among the servants of Zeus, and his appointed duty is to provide wood of specific, prescribed type for the sacrifices, both to the cities and to any private individual. He supplies only poplar wood, and no other tree at all. Whoever, whether one of the Eleans themselves or a foreigner, eats of the meat from the sacrificial victim offered to Pelops, is not permitted to enter the sanctuary of Zeus. The same restriction occurs in Pergamum beyond the river Caïcus for those who sacrifice to Telephus, for neither are these permitted to ascend to the sanctuary of Asclepius without having first bathed.