Passage 4.17.4
περιῆλθε μέντοι καὶ αὐτοὺς Λακεδαιμονίους ἀνὰ χρόνον ἡ Νεοπτολέμειος καλουμένη τίσις. Νεοπτολέμῳ γὰρ τῷ Ἀχιλλέως, ἀποκτείναντι Πρίαμον ἐπὶ τῇ ἐσχάρᾳ τοῦ Ἑρκείου, συνέπεσε καὶ αὐτὸν ἐν Δελφοῖς πρὸς τῷ βωμῷ τοῦ Ἀπόλλωνος ἀποσφαγῆναι· καὶ ἀπὸ τούτου τὸ παθεῖν ὁποῖόν τις καὶ ἔδρασε Νεοπτολέμειον τίσιν ὀνομάζουσι.
Yet in due time the Lacedaemonians themselves also experienced the so-called "punishment of Neoptolemus." Neoptolemus, son of Achilles, had slain Priam upon the altar of Zeus Herkeios, and afterwards he himself was likewise slain at Delphi at the altar of Apollo. Due to this occurrence, the suffering of one who endures a fate similar to that he has previously inflicted is called the "punishment of Neoptolemus."