[Tywin Lannister]
But what makes a good king, hm?
What is a good king's single most important quality?

[Tommen Baratheon]
Holiness? (hm)
Justice?

[Tywin]
Hm... a good king must be just

[Tommen]
What about strength?

[Tywin]
Yes, strength...

[Tommen]
Wisdom! (Yes!)
Wisdom is what makes a good king!

[Tywin]
Yes! A wise king knows what he knows and what he doesn't