How did <PERSON>'s lessons prepare <PERSON> for war with the Shadows?
How did <PERSON>'s training help <PERSON> fight the Shadows?
In season 2, episode 13 of Babylon 5 (Hunter, Prey) <PERSON> says he will teach <PERSON>.
<PERSON>: I will teach you.
<PERSON>: About yourself?
<PERSON>: About you. Until you are ready.
<PERSON>: For what?
<PERSON>: To fight legends.
The period that <PERSON> was giving <PERSON> lessons covered at minimum the time between episode 13 and episode 15 (There All the Honor Lies). In episode 15, <PERSON>'s lesson was experiencing a moment of perfect beauty:
<PERSON>: What, you want me to go inside, is that it? Why? What's inside there?
<PERSON>: One moment of perfect beauty.
[<PERSON> experiences one moment of perfect beauty.]
<PERSON>: I had no idea. No idea at all!
<PERSON>: Yes.
The only example I can think of where <PERSON> directly referenced <PERSON>'s teachings in the Great War was in season 4, episode 6 (Into The Fire) where <PERSON> quoted <PERSON> when confronting the Shadows and the <PERSON>:
<PERSON>: A <PERSON> said, “Understanding is a three-edged sword,” your side, their side, and the truth. Well the truth is we don’t need you anymore!
What did <PERSON> teach <PERSON>? How did it prepare <PERSON> for the war with the Shadows?
EDIT: <PERSON> in the comments brought up that <PERSON> laters specifically asks <PERSON> to teach him to fight the Shadows in season 2, episode 16 (In the Shadow of Z'ha'dum).
Capt. <PERSON>: I let him go. But there is a price tag attached. 663
You've been teaching me so we can understand each other. That's not what I want any more. I want you to teach me... how to fight them. How to beat them. Because one day I'm going to go to Z'ha'dum and I'm going to stop them.
<PERSON>: If you go to Z'ha'dum, you will die.
Capt. <PERSON>: Then I die, but I will not go down easily, I will not go down alone! You will teach me?
<PERSON>: Yes.
From the dialogue it seems plausible that <PERSON> taught <PERSON> about Shadow strategies and their psychology, though none of that is shown. 417