Choephori
From LSJ
Βουλὴν ἅπαντος πράγματος προλάμβανε → Nihil incohes, nisi inito consilio prius → Vor jedem Handeln fasse einen guten Plan
Wikipedia EN
In The Libation Bearers, Libation-Bearers (Χοηφóρoι, Choēphóroi, Choephoroe, Choephori)—the second play of Aeschylus' Oresteia trilogy—many years after the murder of Agamemnon, his son Orestes returns to Argos with his cousin Pylades to exact vengeance on Clytemnestra, as an order from Apollo, for killing Agamemnon.