“He harms himself who does harm to another, and the evil plan is most harmful to the planner.”
Hesiod book Works and Days
οἷ γ᾽ αὐτῷ κακὰ τεύχει ἀνὴρ ἄλλῳ κακὰ τεύχων<br>ἡ δὲ κακὴ βουλὴ τῷ βουλεύσαντι κακίστη. <br class="br">The man who does evil to another does evil to himself, and the evil counsel is most evil for him who counsels it. <br class="br">He for himself weaves woe who weaves for others woe,<br>and evil counsel recoils on the counsellor. https://archive.org/stream/b24865898#page/432/mode/2up <br class="br">Source: Works and Days (c. 700 BC), lines 265-266