"[lecture before the first simulated starship mission] What a fine collection of warriors... so eager for battle. Are you prepared to destroy your enemies? [the cadets cheer and shout in the affirmative] Really... today, you will fire the first shots in a campaign that will lead to the destruction of the Federation. This campaign is not real... but I assure you, it will be worse than real. If you can defeat them in my simulated trials, you will be able to defeat them anywhere, at any time. I believe you know when an enemy intends you harm... but are you truly prepared? Have you meticulously observed your enemy? Have you discerned his weaknesses, appraised his strengths, discovered his greatest hopes and fears? To know your enemy is to defeat him before you have faced him. Do not wait until you meet him in the coldness of space, for space is the harshest instructor."
January 1, 1970
https://en.wikiquote.org/wiki/Star_Trek%3A_Klingon_Academy